(paste from the info line)

abdaominopelvic cavity

division of the anterior (ventral) cavity that houses the abdominal and pelvic viscera

abdominal aorta

portion of the aorta inferior to the aortic hiatus and superior to the common iliac arteries

abduct

move away from midline in the sagittal plane

abduction

movement in the coronal plane that moves a limb laterally away from the body; spreading of the fingers

abductor

moves the bone away from the midline

abductor digiti minimi

muscle that abducts the little finger

adductor pollicis

muscle that adducts the thumb

abductor pollicis brevis

muscle that abducts the thumb

abductor pollicis longus

muscle that inserts into the first metacarpal

ABO blood group

blood-type classification based on the presence or absence of A and B glycoproteins on the erythrocyte membrane surface

acclimatization

process of adjustment that the respiratory system makes due to chronic exposure to high altitudes

acetabular labrum

lip of fibrocartilage that surrounds outer margin of the acetabulum on the hip bone

acetabulum

large, cup-shaped cavity located on the lateral side of the hip bone; formed by the junction of the ilium, pubis, and ischium portions of the hip bone

acetylcholine (ACh)

neurotransmitter that binds at a motor end-plate to trigger depolarization

acetylcholine (ACh)

neurotransmitter that binds at a motor end-plate to trigger depolarization

acid

building block of proteins; characterized by an amino and carboxyl functional groups and a variable side-chain

acromial process

acromion of the scapula

acromioclavicular joint

articulation between the acromion of the scapula and the acromial end of the clavicle

acromion

flattened bony process that extends laterally from the scapular spine to form the bony tip of the shoulder

acrosome

cap-like vesicle located at the anterior-most region of a sperm that is rich with lysosomal enzymes capable of digesting the protective layers surrounding the oocyte

acrosomal reaction

release of digestive enzymes by sperm that enables them to burrow through the corona radiata and penetrate the zona pellucida of an oocyte prior to fertilization

actin

protein that makes up most of the thin myofilaments in a sarcomere muscle fiber

actin

protein that makes up most of the thin myofilaments in a sarcomere muscle fiber

action potential

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers

action potential

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers

activation energy

amount of energy greater than the energy contained in the reactants, which must be overcome for a reaction to proceed

active immunity

immunity developed from an individual’s own immune system

active transport

form of transport across the cell membrane that requires the input of cellular energy

acute inflammation

inflammation occurring for a limited time period; rapidly developing

acute mountain sickness (AMS)

condition that occurs a result of acute exposure to high altitude due to a low partial pressure of oxygen

adaptive immune response

relatively slow but very specific and effective immune response controlled by lymphocytes

adductor

moves the bone toward the midline

adductor brevis

muscle that adducts and medially rotates the thigh

adductor longus

muscle that adducts, medially rotates, and flexes the thigh

adductor magnus

muscle with an anterior fascicle that adducts, medially rotates and flexes the thigh, and a posterior fascicle that assists in thigh extension

adenosine triphosphate (ATP)

nucleotide containing ribose and an adenine base that is essential in energy transfer

adipocytes

lipid storage cells

adipose tissue

specialized areolar tissue rich in stored fat

adductor tubercle

small, bony bump located on the superior aspect of the medial epicondyle of the femur

adduction

movement in the coronal plane that moves a limb medially toward or across the midline of the body; bringing fingers together

adrenal artery

branch of the abdominal aorta; supplies blood to the adrenal (suprarenal) glands

adrenal vein

drains the adrenal or suprarenal glands that are immediately superior to the kidneys; the right adrenal vein enters the inferior vena cava directly and the left adrenal vein enters the left renal vein

aerobic respiration

production of ATP in the presence of oxygen

afferent lymphatic vessels

lead into a lymph node

afterload

force the ventricles must develop to effectively pump blood against the resistance in the vessels

agglutination

clustering of cells into masses linked by antibodies

agonist

(also, prime mover) muscle whose contraction is responsible for producing a particular motion

albinism

genetic disorder that affects the skin, in which there is no melanin production

albumin

most abundant plasma protein, accounting for most of the osmotic pressure of plasma

alveolar dead space

air space within alveoli that are unable to participate in gas exchange

alveolar duct

small tube that leads from the terminal bronchiole to the respiratory bronchiole and is the point of attachment for alveoli

alveolar macrophage

immune system cell of the alveolus that removes debris and pathogens

alveolar pore

opening that allows airflow between neighboring alveoli

alveolar process of the mandible

upper border of mandibular body that contains the lower teeth

alveolar process of the maxilla

curved, inferior margin of the maxilla that supports and anchors the upper teeth

alveolar sac

cluster of alveoli

alveolus

small, grape-like sac that performs gas exchange in the lungs

amino acid

building block of proteins; characterized by an amino and carboxyl functional groups and a variable side-chain

amphipathic

describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility

amphiarthrosis

slightly mobile joint

anal triangle

posterior triangle of the perineum that includes the anus

anaphase

third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell

anaphylactic shock

type of shock that follows a severe allergic reaction and results from massive vasodilation

anastomosis

(plural = anastomoses) area where vessels unite to allow blood to circulate even if there may be partial blockage in another branch

anatomical dead space

air space present in the airway that never reaches the alveoli and therefore never participates in gas exchange

anatomical neck

line on the humerus located around the outside margin of the humeral head

anatomical position

standard reference position used for describing locations and directions on the human body

anatomy

science that studies the form and composition of the body’s structures

anagen

active phase of the hair growth cycle

anconeus

small muscle on the lateral posterior elbow that extends the forearm

anemia

deficiency of red blood cells or hemoglobin

angiogenesis

formation of blood capillary networks

angle of the mandible

rounded corner located at outside margin of the body and ramus junction

angle of the rib

portion of rib with greatest curvature; together, the rib angles form the most posterior extent of the thoracic cage

anion

atom with a negative charge

ankle joint

joint that separates the leg and foot portions of the lower limb; formed by the articulations between the talus bone of the foot inferiorly, and the distal end of the tibia, medial malleolus of the tibia, and lateral malleolus of the fibula superiorly

annular ligament

intrinsic ligament of the elbow articular capsule that surrounds and supports the head of the radius at the proximal radioulnar joint

antagonist

muscle that opposes the action of an agonist

anterior

describes the front or direction toward the front of the body; also referred to as ventral

anterior arch

anterior portion of the ring-like C1 (atlas) vertebra

anterior cerebral artery

arises from the internal carotid artery; supplies the frontal lobe of the cerebrum

anterior communicating artery

anastomosis of the right and left internal carotid arteries; supplies blood to the brain

anterior border of the tibia

narrow, anterior margin of the tibia that extends inferiorly from the tibial tuberosity

anterior cardiac veins

vessels that parallel the small cardiac arteries and drain the anterior surface of the right ventricle; bypass the coronary sinus and drain directly into the right atrium

anterior cavity

larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as ventral cavity

anterior compartment of the arm

(anterior flexor compartment of the arm) the biceps brachii, brachialis, brachioradialis, and their associated blood vessels and nerves

anterior compartment of the forearm

(anterior flexor compartment of the forearm) deep and superficial muscles that originate on the humerus and insert into the hand

anterior compartment of the leg

region that includes muscles that dorsiflex the foot

anterior compartment of the thigh

region that includes muscles that flex the thigh and extend the leg

anterior cranial fossa

shallowest and most anterior cranial fossa of the cranial base that extends from the frontal bone to the lesser wing of the sphenoid bone

anterior cruciate ligament

intracapsular ligament of the knee; extends from anterior, superior surface of the tibia to the inner aspect of the lateral condyle of the femur; resists hyperextension of knee

anterior inferior iliac spine

small, bony projection located on the anterior margin of the ilium, below the anterior superior iliac spine

anterior interventricular artery

(also, left anterior descending artery or LAD) major branch of the left coronary artery that follows the anterior interventricular sulcus

anterior interventricular sulcus

sulcus located between the left and right ventricles on the anterior surface of the heart

anterior longitudinal ligament

ligament that runs the length of the vertebral column, uniting the anterior aspects of the vertebral bodies

anterior (ventral) sacral foramen

one of the series of paired openings located on the anterior (ventral) side of the sacrum

anterior sacroiliac ligament

strong ligament between the sacrum and the ilium portions of the hip bone that supports the anterior side of the sacroiliac joint

anterior scalene

a muscle anterior to the middle scalene

anterior superior iliac spine

rounded, anterior end of the iliac crest

anterior talofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between talus bone and lateral malleolus of fibula; supports talus at the talocrural joint and resists excess inversion of the foot

anterior tibial artery

branches from the popliteal artery; supplies blood to the anterior tibial region; becomes the dorsalis pedis artery

anterior tibial vein

forms from the dorsal venous arch; drains the area near the tibialis anterior muscle and leads to the popliteal vein

antibodies

(also, immunoglobulins or gamma globulins) antigen-specific proteins produced by specialized B lymphocytes that protect the body by binding to foreign objects such as bacteria and viruses

antibody

antigen-specific protein secreted by plasma cells; immunoglobulin

anticoagulant

substance such as heparin that opposes coagulation

anticodon

consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule

antigen

molecule recognized by the receptors of B and T lymphocytes

antigenic determinant

(also, epitope) one of the chemical groups recognized by a single type of lymphocyte antigen receptor

antigen presentation

binding of processed antigen to the protein-binding cleft of a major histocompatibility complex molecule

antigen processing

internalization and digestion of antigen in an antigen-presenting cell

antigen receptor

two-chain receptor by which lymphocytes recognize antigen

antithrombin

anticoagulant that inactivates factor X and opposes the conversion of prothrombin (factor II) into thrombin in the common pathway

anulus fibrosus

tough, fibrous outer portion of an intervertebral disc, which is strongly anchored to the bodies of the adjacent vertebrae

aorta

largest artery in the body, originating from the left ventricle and descending to the abdominal region where it bifurcates into the common iliac arteries at the level of the fourth lumbar vertebra; arteries originating from the aorta distribute blood to virtually all tissues of the body

aortic arch

arc that connects the ascending aorta to the descending aorta; ends at the intervertebral disk between the fourth and fifth thoracic vertebrae

aortic hiatus

opening in the diaphragm that allows passage of the thoracic aorta into the abdominal region where it becomes the abdominal aorta

aortic sinuses

small pockets in the ascending aorta near the aortic valve that are the locations of the baroreceptors (stretch receptors) and chemoreceptors that trigger a reflex that aids in the regulation of vascular homeostasis

aortic valve

(also, aortic semilunar valve) valve located at the base of the aorta

apex

tip of the external nose

apical ectodermal ridge

enlarged ridge of ectoderm at the distal end of a limb bud that stimulates growth and elongation of the limb

appendicular skeleton

all bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton

apneustic center

network of neurons within the pons that stimulate the neurons in the dorsal respiratory group; controls the depth of inspiration

apocrine sweat gland

type of sweat gland that is associated with hair follicles in the armpits and genital regions

aponeurosis

broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone

aponeurosis

broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone

appendicular

of the arms and legs

arcuate line of the ilium

smooth ridge located at the inferior margin of the iliac fossa; forms the lateral portion of the pelvic brim

arrector pili

smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”

areolar tissue

(also, loose connective tissue) a type of connective tissue proper that shows little specialization with cells dispersed in the matrix

arm

region of the upper limb located between the shoulder and elbow joints; contains the humerus bone

arterial circle

(also, circle of Willis) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain

arteriole

(also, resistance vessel) very small artery that leads to a capillary

arteriovenous anastomosis

short vessel connecting an arteriole directly to a venule and bypassing the capillary beds

artery

blood vessel that conducts blood away from the heart; may be a conducting or distributing vessel

articular cartilage

thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber

articular tubercle

smooth ridge located on the inferior skull, immediately anterior to the mandibular fossa

articulation

joint of the body/where two bone surfaces meet

artificial pacemaker

medical device that transmits electrical signals to the heart to ensure that it contracts and pumps blood to the body

ascending aorta

initial portion of the aorta, rising from the left ventricle for a distance of approximately 5 cm

astrocyte

star-shaped cell in the central nervous system that regulates ions and uptake and/or breakdown of some neurotransmitters and contributes to the formation of the blood-brain barrier

atlantoaxial joint

series of three articulations between the atlas (C1) vertebra and the axis (C2) vertebra, consisting of the joints between the inferior articular processes of C1 and the superior articular processes of C2, and the articulation between the dens of C2 and the anterior arch of C1

atlanto-occipital joint

articulation between the occipital condyles of the skull and the superior articular processes of the atlas (C1 vertebra)

atlas

first cervical (C1) vertebrae

atmospheric pressure

amount of force that is exerted by gases in the air surrounding any given surface

atom

smallest unit of an element that retains the unique properties of that element

atomic number

number of protons in the nucleus of an atom

ATPase

enzyme that hydrolyzes ATP to ADP

atrial reflex

(also, called Bainbridge reflex) autonomic reflex that responds to stretch receptors in the atria that send impulses to the cardioaccelerator area to increase HR when venous flow into the atria increases

atrial reflex

mechanism for maintaining vascular homeostasis involving atrial baroreceptors: if blood is returning to the right atrium more rapidly than it is being ejected from the left ventricle, the atrial receptors will stimulate the cardiovascular centers to increase sympathetic firing and increase cardiac output until the situation is reversed; the opposite is also true

atrioventricular bundle

(also, bundle of His) group of specialized myocardial conductile cells that transmit the impulse from the AV node through the interventricular septum; form the left and right atrioventricular bundle branches

atrioventricular bundle branches

(also, left or right bundle branches) specialized myocardial conductile cells that arise from the bifurcation of the atrioventricular bundle and pass through the interventricular septum; lead to the Purkinje fibers and also to the right papillary muscle via the moderator band

atrioventricular (AV) node

clump of myocardial cells located in the inferior portion of the right atrium within the atrioventricular septum; receives the impulse from the SA node, pauses, and then transmits it into specialized conducting cells within the interventricular septum

atrioventricular septum

cardiac septum located between the atria and ventricles; atrioventricular valves are located here

atrioventricular valves

one-way valves located between the atria and ventricles; the valve on the right is called the tricuspid valve, and the one on the left is the mitral or bicuspid valve

atrium

(plural = atria) upper or receiving chamber of the heart that pumps blood into the lower chambers just prior to their contraction; the right atrium receives blood from the systemic circuit that flows into the right ventricle; the left atrium receives blood from the pulmonary circuit that flows into the left ventricle

atrophy

loss of structural proteins from muscle fibers

auricle

extension of an atrium visible on the superior surface of the heart

autolysis

breakdown of cells by their own enzymatic action

autonomic tone

contractile state during resting cardiac activity produced by mild sympathetic and parasympathetic stimulation

autorhythmicity

ability of cardiac muscle to initiate its own electrical impulse that triggers the mechanical contraction that pumps blood at a fixed pace without nervous or endocrine control

auricular surface of the ilium

roughened area located on the posterior, medial side of the ilium of the hip bone; articulates with the auricular surface of the sacrum to form the sacroiliac joint

autophagy

lysosomal breakdown of a cell’s own components

axial

of the trunk and head

axial skeleton

central, vertical axis of the body, including the skull, vertebral column, and thoracic cage

axillary artery

continuation of the subclavian artery as it penetrates the body wall and enters the axillary region; supplies blood to the region near the head of the humerus (humeral circumflex arteries); the majority of the vessel continues into the brachium and becomes the brachial artery

axillary vein

major vein in the axillary region; drains the upper limb and becomes the subclavian vein

axis

second cervical (C2) vertebra

azygos vein

originates in the lumbar region and passes through the diaphragm into the thoracic cavity on the right side of the vertebral column; drains blood from the intercostal veins, esophageal veins, bronchial veins, and other veins draining the mediastinal region; leads to the superior vena cava

basal cell

type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis

basal metabolic rate (BMR)

amount of energy expended by the body at rest

base

compound that accepts hydrogen ions (H⁺) in solution

base of the metatarsal bone

expanded, proximal end of each metatarsal bone

basilar artery

formed from the fusion of the two vertebral arteries; sends branches to the cerebellum, brain stem, and the posterior cerebral arteries; the main blood supply to the brain stem

basilic vein

superficial vein of the arm that arises from the palmar venous arches, intersects with the median cubital vein, parallels the ulnar vein, and continues into the upper arm; along with the brachial vein, it leads to the axillary vein

basophils

granulocytes that stain with a basic (alkaline) stain and store histamine and heparin

B cells

lymphocytes that act by differentiating into an antibody-secreting plasma cell

belly

bulky central body of a muscle

bi

two

biaxial joint

type of diarthrosis; a joint that allows for movements within two planes (two axes)

biceps brachii

two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder

biceps femoris

hamstring muscle

bicipital groove

intertubercular groove; narrow groove located between the greater and lesser tubercles of the humerus

bicuspid valve

(also, mitral valve or left atrioventricular valve) valve located between the left atrium and ventricle; consists of two flaps of tissue

bilirubin

yellowish bile pigment produced when iron is removed from heme and is further broken down into waste products

biliverdin

green bile pigment produced when the non-iron portion of heme is degraded into a waste product; converted to bilirubin in the liver

bipennate

pennate muscle that has fascicles that are located on both sides of the tendon

blood

liquid connective tissue composed of formed elements—erythrocytes, leukocytes, and platelets—and a fluid extracellular matrix called plasma; component of the cardiovascular system

blood colloidal osmotic pressure (BCOP)

pressure exerted by colloids suspended in blood within a vessel; a primary determinant is the presence of plasma proteins

blood flow

movement of blood through a vessel, tissue, or organ that is usually expressed in terms of volume per unit of time

blood hydrostatic pressure

force blood exerts against the walls of a blood vessel or heart chamber

blood pressure

force exerted by the blood against the wall of a vessel or heart chamber; can be described with the more generic term hydrostatic pressure

B lymphocytes

(also, B cells) lymphocytes that defend the body against specific pathogens and thereby provide specific immunity

body of the rib

shaft portion of a rib

Bohr effect

relationship between blood pH and oxygen dissociation from hemoglobin

bond

electrical force linking atoms

bone

hard, dense connective tissue that forms the structural elements of the skeleton

bone marrow

tissue found inside bones; the site of all blood cell differentiation and maturation of B lymphocytes

bone marrow biopsy

diagnostic test of a sample of red bone marrow

bone marrow transplant

treatment in which a donor’s healthy bone marrow with its stem cells replaces diseased or damaged bone marrow of a patient

Boyle’s law

relationship between volume and pressure as described by the formula: P₁V₁ = P₂V₂

brachial artery

continuation of the axillary artery in the brachium; supplies blood to much of the brachial region; gives off several smaller branches that provide blood to the posterior surface of the arm in the region of the elbow; bifurcates into the radial and ulnar arteries at the coronoid fossa

brachialis

muscle deep to the biceps brachii that provides power in flexing the forearm.

brachial vein

deeper vein of the arm that forms from the radial and ulnar veins in the lower arm; leads to the axillary vein

brachiocephalic artery

single vessel located on the right side of the body; the first vessel branching from the aortic arch; gives rise to the right subclavian artery and the right common carotid artery; supplies blood to the head, neck, upper limb, and wall of the thoracic region

brachiocephalic vein

one of a pair of veins that form from a fusion of the external and internal jugular veins and the subclavian vein; subclavian, external and internal jugulars, vertebral, and internal thoracic veins lead to it; drains the upper thoracic region and flows into the superior vena cava

bronchial artery

systemic branch from the aorta that provides oxygenated blood to the lungs in addition to the pulmonary circuit

bronchial vein

drains the systemic circulation from the lungs and leads to the azygos vein

brachioradialis

muscle that can flex the forearm quickly or help lift a load slowly

brain case

portion of the skull that contains and protects the brain, consisting of the eight bones that form the cranial base and rounded upper skull

brevis

short

bridge

portion of the external nose that lies in the area of the nasal bones

bronchial tree

collective name for the multiple branches of the bronchi and bronchioles of the respiratory system

bronchoconstriction

decrease in the size of the bronchiole due to contraction of the muscular wall

bronchodilation

increase in the size of the bronchiole due to contraction of the muscular wall

bronchus-associated lymphoid tissue (BALT)

lymphoid nodule associated with the respiratory tract

bronchiole

branch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs

bronchus

tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs

buccinator

muscle that compresses the cheek

buffer

solution containing a weak acid or a weak base that opposes wide fluctuations in the pH of body fluids

buffy coat

thin, pale layer of leukocytes and platelets that separates the erythrocytes from the plasma in a sample of centrifuged blood

bundle of His

(also, atrioventricular bundle) group of specialized myocardial conductile cells that transmit the impulse from the AV node through the interventricular septum; form the left and right atrioventricular bundle branches

calcaneal tendon

(also, Achilles tendon) strong tendon that inserts into the calcaneal bone of the ankle

calcaneofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between the calcaneus bone and lateral malleolus of the fibula; supports the talus bone at the ankle joint and resists excess inversion of the foot

calcaneus

heel bone; posterior, inferior tarsal bone that forms the heel of the foot

calvaria

(also, skullcap) rounded top of the skull

canaliculi

(singular = canaliculus) channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients

capacitation

process that occurs in the female reproductive tract in which sperm are prepared for fertilization; leads to increased motility and changes in their outer membrane that improve their ability to release enzymes capable of digesting an oocyte’s outer layers

capacitance

ability of a vein to distend and store blood

capacitance vessels

veins

capillary

smallest of blood vessels where physical exchange occurs between the blood and tissue cells surrounded by interstitial fluid

capillary bed

network of 10–100 capillaries connecting arterioles to venules

capillary hydrostatic pressure (CHP)

force blood exerts against a capillary

capitate

from the lateral side, the third of the four distal carpal bones; articulates with the scaphoid and lunate proximally, the trapezoid laterally, the hamate medially, and primarily with the third metacarpal distally

capitulum

knob-like bony structure located anteriorly on the lateral, distal end of the humerus

carbaminohemoglobin

compound of carbon dioxide and hemoglobin, and one of the ways in which carbon dioxide is carried in the blood

carbaminohemoglobin

bound form of hemoglobin and carbon dioxide

carbohydrate

class of organic compounds built from sugars, molecules containing carbon, hydrogen, and oxygen in a 1-2-1 ratio

carbonic anhydrase (CA)

enzyme that catalyzes the reaction that causes carbon dioxide and water to form carbonic acid

cardiac cycle

period of time between the onset of atrial contraction (atrial systole) and ventricular relaxation (ventricular diastole)

cardiac muscle

heart muscle, under involuntary control, composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously

cardiac muscle

striated muscle found in the heart; joined to one another at intercalated discs and under the regulation of pacemaker cells, which contract as one unit to pump blood through the circulatory system. Cardiac muscle is under involuntary control

cardiac notch

depression in the medial surface of the inferior lobe of the left lung where the apex of the heart is located

cardiac notch

indentation on the surface of the left lung that allows space for the heart

cardiac output (CO)

amount of blood pumped by each ventricle during one minute; equals HR multiplied by SV

cardiac plexus

paired complex network of nerve fibers near the base of the heart that receive sympathetic and parasympathetic stimulations to regulate HR

cardiac reflexes

series of autonomic reflexes that enable the cardiovascular centers to regulate heart function based upon sensory information from a variety of visceral sensors

cardiac reserve

difference between maximum and resting CO

cardiac skeleton

(also, skeleton of the heart) reinforced connective tissue located within the atrioventricular septum; includes four rings that surround the openings between the atria and ventricles, and the openings to the pulmonary trunk and aorta; the point of attachment for the heart valves

cardiogenic shock

type of shock that results from the inability of the heart to maintain cardiac output

cardiomyocyte

muscle cell of the heart

carotid canal

zig-zag tunnel providing passage through the base of the skull for the internal carotid artery to the brain; begins anteromedial to the styloid process and terminates in the middle cranial cavity, near the posterior-lateral base of the sella turcica

carotid sinuses

small pockets near the base of the internal carotid arteries that are the locations of the baroreceptors and chemoreceptors that trigger a reflex that aids in the regulation of vascular homeostasis

carpal bone

one of the eight small bones that form the wrist and base of the hand; these are grouped as a proximal row consisting of (from lateral to medial) the scaphoid, lunate, triquetrum, and pisiform bones, and a distal row containing (from lateral to medial) the trapezium, trapezoid, capitate, and hamate bones

carpal tunnel

passageway between the anterior forearm and hand formed by the carpal bones and flexor retinaculum

carpometacarpal joint

articulation between one of the carpal bones in the distal row and a metacarpal bone of the hand

cartilaginous joint

joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis)

cartilage

semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement

catagen

transitional phase marking the end of the anagen phase of the hair growth cycle

catalyst

substance that increases the rate of a chemical reaction without itself being changed in the process

cation

atom with a positive charge

caudal

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as inferior

caval opening

opening in the diaphragm that allows the inferior vena cava to pass through; foramen for the vena cava

cavernous sinus

enlarged vein that receives blood from most of the other cerebral veins and the eye socket, and leads to the petrosal sinus

celiac trunk

(also, celiac artery) major branch of the abdominal aorta; gives rise to the left gastric artery, the splenic artery, and the common hepatic artery that forms the hepatic artery to the liver, the right gastric artery to the stomach, and the cystic artery to the gall bladder

cell cycle

life cycle of a single cell, from its birth until its division into two new daughter cells

cell membrane

membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane

centriole

small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division

central canal

longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal

central chemoreceptor

one of the specialized receptors that are located in the brain that sense changes in hydrogen ion, oxygen, or carbon dioxide concentrations in the brain

cephalic vein

superficial vessel in the upper arm; leads to the axillary vein

cerebrovascular accident (CVA)

blockage of blood flow to the brain; also called a stroke

cervical curve

posteriorly concave curvature of the cervical vertebral column region; a secondary curve of the vertebral column

cervical vertebrae

seven vertebrae numbered as C1–C7 that are located in the neck region of the vertebral column

central tolerance

B cell tolerance induced in immature B cells of the bone marrow

centromere

region of attachment for two sister chromatids

centrosome

cellular structure that organizes microtubules during cell division

channel protein

membrane-spanning protein that has an inner pore which allows the passage of one or more substances

checkpoint

progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase

chemical energy

form of energy that is absorbed as chemical bonds form, stored as they are maintained, and released as they are broken

chemokine

soluble, long-range, cell-to-cell communication molecule

chloride shift

facilitated diffusion that exchanges bicarbonate (HCO₃^–) with chloride (Cl^–) ions

chondrocytes

cells of the cartilage

chordae tendineae

string-like extensions of tough connective tissue that extend from the flaps of the atrioventricular valves to the papillary muscles

chromatin

substance consisting of DNA and associated proteins

chromosome

condensed version of chromatin

chronic inflammation

inflammation occurring for long periods of time

chyle

lipid-rich lymph inside the lymphatic capillaries of the small intestine

cilia

small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface

circle of Willis

(also, arterial circle) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain

circular

(also, sphincter) fascicles that are concentrically arranged around an opening

circulatory shock

also simply called shock; a life-threatening medical condition in which the circulatory system is unable to supply enough blood flow to provide adequate oxygen and other nutrients to the tissues to maintain cellular metabolism

circumduction

circular motion of the arm, thigh, hand, thumb, or finger that is produced by the sequential combination of flexion, abduction, extension, and adduction

circumflex artery

branch of the left coronary artery that follows coronary sulcus

cisterna chyli

bag-like vessel that forms the beginning of the thoracic duct

class switching

ability of B cells to change the class of antibody they produce without altering the specificity for antigen

clavicle

collarbone; elongated bone that articulates with the manubrium of the sternum medially and the acromion of the scapula laterally

clavicular notch

paired notches located on the superior-lateral sides of the sternal manubrium, for articulation with the clavicle

cleavage furrow

contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves

clone

group of lymphocytes sharing the same antigen receptor

clonal anergy

process whereby B cells that react to soluble antigens in bone marrow are made nonfunctional

clonal deletion

removal of self-reactive B cells by inducing apoptosis

clonal expansion

growth of a clone of selected lymphocytes

clonal selection

stimulating growth of lymphocytes that have specific receptors

closed reduction

manual manipulation of a broken bone to set it into its natural position without surgery

clotting factors

group of 12 identified substances active in coagulation

coagulation

formation of a blood clot; part of the process of hemostasis

coccyx

small bone located at inferior end of the adult vertebral column that is formed by the fusion of four coccygeal vertebrae; also referred to as the “tailbone”

codon

consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid

colloid

liquid mixture in which the solute particles consist of clumps of molecules large enough to scatter light

collagen fiber

flexible fibrous proteins that give connective tissue tensile strength

colony-stimulating factors (CSFs)

glycoproteins that trigger the proliferation and differentiation of myeloblasts into granular leukocytes (basophils, neutrophils, and eosinophils)

common carotid artery

right common carotid artery arises from the brachiocephalic artery, and the left common carotid arises from the aortic arch; gives rise to the external and internal carotid arteries; supplies the respective sides of the head and neck

common hepatic artery

branch of the celiac trunk that forms the hepatic artery, the right gastric artery, and the cystic artery

common iliac artery

branch of the aorta that leads to the internal and external iliac arteries

common iliac vein

one of a pair of veins that flows into the inferior vena cava at the level of L5; the left common iliac vein drains the sacral region; divides into external and internal iliac veins near the inferior portion of the sacroiliac joint

common pathway

final coagulation pathway activated either by the intrinsic or the extrinsic pathway, and ending in the formation of a blood clot

compliance

degree to which a blood vessel can stretch as opposed to being rigid

compound

substance composed of two or more different elements joined by chemical bonds

compact bone

dense osseous tissue that can withstand compressive forces

complement

enzymatic cascade of constitutive blood proteins that have antipathogen effects, including the direct killing of bacteria

compressor urethrae

deep perineal muscle in women

concentration

number of particles within a given space

concentration gradient

difference in the concentration of a substance between two regions

concentric contraction

muscle contraction that shortens the muscle to move a load

conducting zone

region of the respiratory system that includes the organs and structures that provide passageways for air and are not directly involved in gas exchange

conduction

transfer of heat through physical contact

condylar process of the mandible

thickened upward projection from posterior margin of mandibular ramus

condyle

oval-shaped process located at the top of the condylar process of the mandible

connective tissue

type of tissue that serves to hold in place, connect, and integrate the body’s organs and systems

connective tissue membrane

connective tissue that encapsulates organs and lines movable joints

connective tissue proper

connective tissue containing a viscous matrix, fibers, and cells.

constant region domain

part of a lymphocyte antigen receptor that does not vary much between different receptor types

continuous capillary

most common type of capillary, found in virtually all tissues except epithelia and cartilage; contains very small gaps in the endothelial lining that permit exchange

contractility

ability to shorten (contract) forcibly

contraction phase

twitch contraction phase when tension increases

control center

compares values to their normal range; deviations cause the activation of an effector

convection

transfer of heat between the skin and air or water

convergent

fascicles that extend over a broad area and converge on a common attachment site

coracobrachialis

muscle that flexes and adducts the arm

coracoclavicular ligament

strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle; provides important indirect support for the acromioclavicular joint

coracoid process

short, hook-like process that projects anteriorly and laterally from the superior margin of the scapula

corona radiata

in an oocyte, a layer of granulosa cells that surrounds the oocyte and that must be penetrated by sperm before fertilization can occur

coronal suture

joint that unites the frontal bone to the right and left parietal bones across the top of the skull

coronary arteries

branches of the ascending aorta that supply blood to the heart; the left coronary artery feeds the left side of the heart, the left atrium and ventricle, and the interventricular septum; the right coronary artery feeds the right atrium, portions of both ventricles, and the heart conduction system

coronary sinus

large, thin-walled vein on the posterior surface of the heart that lies within the atrioventricular sulcus and drains the heart myocardium directly into the right atrium

coronary sulcus

sulcus that marks the boundary between the atria and ventricles

coronary veins

vessels that drain the heart and generally parallel the large surface arteries

coronoid fossa

depression on the anterior surface of the humerus above the trochlea; this space receives the coronoid process of the ulna when the elbow is maximally flexed

coronoid process of the mandible

flattened upward projection from the anterior margin of the mandibular ramus

coronoid process of the ulna

projecting bony lip located on the anterior, proximal ulna; forms the inferior margin of the trochlear notch

corrugator supercilii

prime mover of the eyebrows

cortex

in hair, the second or middle layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb

cortical reaction

following fertilization, the release of cortical granules from the oocyte’s plasma membrane into the zona pellucida creating a fertilization membrane that prevents any further attachment or penetration of sperm; part of the slow block to polyspermy

costal cartilage

hyaline cartilage structure attached to the anterior end of each rib that provides for either direct or indirect attachment of most ribs to the sternum

costal facet

site on the lateral sides of a thoracic vertebra for articulation with the head of a rib

costal groove

shallow groove along the inferior margin of a rib that provides passage for blood vessels and a nerve

costoclavicular ligament

band of connective tissue that unites the medial clavicle with the first rib

covalent bond

broad depression located on the posterio scapula, inferior to the spine chemical bond in which two atoms share electrons, thereby completing their valence shells.

coracohumeral ligament

intrinsic ligament of the shoulder joint; runs from the coracoid process of the scapula to the anterior humerus

coxal bone

hip bone

cranial

describes a position above or higher than another part of the body proper; also referred to as superior

cranial cavity

division of the posterior (dorsal) cavity that houses the brain

cranial cavity

interior space of the skull that houses the brain

cranium

skull

creatine phosphate

phosphagen used to store energy from ATP and transfer it to muscle

cribriform plate

small, flattened areas with numerous small openings, located to either side of the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone

cricoid cartilage

portion of the larynx composed of a ring of cartilage with a wide posterior region and a thinner anterior region; attached to the esophagus

crista galli

small upward projection located at the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone

cross matching

blood test for identification of blood type using antibodies and small samples of blood

cutaneous membrane

skin; epithelial tissue made up of a stratified squamous epithelial cells that cover the outside of the body

cuboid

tarsal bone that articulates posteriorly with the calcaneus bone, medially with the lateral cuneiform bone, and anteriorly with the fourth and fifth metatarsal bones

cuticle

in hair, the outermost layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb

cyclin

one of a group of proteins that function in the progression of the cell cycle

cyclin-dependent kinase (CDK)

one of a group of enzymes associated with cyclins that help them perform their functions

cystic artery

branch of the common hepatic artery; supplies blood to the gall bladder

cytokinesis

final stage in cell division, where the cytoplasm divides to form two separate daughter cells

cytokine

soluble, short-range, cell-to-cell communication molecule

cytokines

class of proteins that act as autocrine or paracrine signaling molecules; in the cardiovascular system, they stimulate the proliferation of progenitor cells and help to stimulate both nonspecific and specific resistance to disease

cytoplasm

internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials

cytoskeleton

“skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities

cytosol

clear, semi-fluid medium of the cytoplasm, made up mostly of water

cytotoxic T cells (Tc)

T lymphocytes with the ability to induce apoptosis in target cells

Dalton’s law

statement of the principle that a specific gas type in a mixture exerts its own pressure, as if that specific gas type was not part of a mixture of gases

deep

describes a position farther from the surface of the body

deep anterior compartment

flexor pollicis longus, flexor digitorum profundus, and their associated blood vessels and nerves

deep femoral artery

branch of the femoral artery; gives rise to the lateral circumflex arteries

deep femoral vein

drains blood from the deeper portions of the thigh and leads to the femoral vein

deep posterior compartment of the forearm

(deep posterior extensor compartment of the forearm) the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, and their associated blood vessels and nerves

deep transverse perineal

deep perineal muscle in men

defensins

antimicrobial proteins released from neutrophils and macrophages that create openings in the plasma membranes to kill cells

deglutition

swallowing

delayed hypersensitivity

(type IV) T cell-mediated immune response against pathogens infiltrating interstitial tissues, causing cellular infiltrate

deltoid

shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it

deltoid ligament

broad intrinsic ligament located on the medial side of the ankle joint; supports the talus at the talocrural joint and resists excess eversion of the foot

deltoid tuberosity

roughened, V-shaped region located laterally on the mid-shaft of the humerus

denaturation

change in the structure of a molecule through physical or chemical means

dens

bony projection (odontoid process) that extends upward from the body of the C2 (axis) vertebra

dense connective tissue

connective tissue proper that contains many fibers that provide both elasticity and protection

deoxyhemoglobin

molecule of hemoglobin without an oxygen molecule bound to it

deoxyribonucleic acid (DNA)

deoxyribose-containing nucleotide that stores genetic information

depolarize

to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest

depression

downward (inferior) motion of the scapula or mandible

dermal papilla

(plural = dermal papillae) extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis

dermis

layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures

descending aorta

portion of the aorta that continues downward past the end of the aortic arch; subdivided into the thoracic aorta and the abdominal aorta

desmosome

structure that forms an impermeable junction between cells

Development is all of the changes the body goes through in life. Development includes the process of differentiation, in which unspecialized cells become specialized in structure and function to perform certain tasks in the body. Development also includes the processes of growth and repair, both of which involve cell differentiation.

diarthrosis

freely mobile joint

diapedesis

(also, emigration) process by which leukocytes squeeze through adjacent cells in a blood vessel wall to enter tissues

diaphragm

skeletal muscle that separates the thoracic and abdominal cavities and is dome-shaped at rest

diaphysis

tubular shaft that runs between the proximal and distal ends of a long bone

diastole

period of time when the heart muscle is relaxed and the chambers fill with blood

diastolic pressure

lower number recorded when measuring arterial blood pressure; represents the minimal value corresponding to the pressure that remains during ventricular relaxation

diffusion

movement of a substance from an area of higher concentration to one of lower concentration

digastric

muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible

digital arteries

formed from the superficial and deep palmar arches; supply blood to the digits

digital veins

drain the digits and feed into the palmar arches of the hand and dorsal venous arch of the foot

diploë

layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones

diploid

condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents)

disaccharide

pair of carbohydrate monomers bonded by dehydration synthesis via a glycosidic bond

disulfide bond

covalent bond formed within a polypeptide between sulfide groups of sulfur-containing amino acids, for example, cysteine

distal

describes a position farther from the point of attachment or the trunk of the body

distal radioulnar joint

articulation between the head of the ulna and the ulnar notch of the radius

distal tibiofibular joint

articulation between the distal fibula and the fibular notch of the tibia

DNA polymerase

enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication

DNA replication

process of duplicating a molecule of DNA

dorsal

describes the back or direction toward the back of the body; also referred to as posterior

dorsal arch

(also, arcuate arch) formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits

dorsal cavity

posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity

dorsal group

region that includes the extensor digitorum brevis

dorsal interossei

muscles that abduct and flex the three middle fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints

dorsal respiratory group (DRG)

region of the medulla oblongata that stimulates the contraction of the diaphragm and intercostal muscles to induce inspiration

dorsal venous arch

drains blood from digital veins and vessels on the superior surface of the foot

dorsalis pedis artery

forms from the anterior tibial artery; branches repeatedly to supply blood to the tarsal and dorsal regions of the foot

dorsiflexion

movement at the ankle that brings the top of the foot toward the anterior leg

dorsum nasi

intermediate portion of the external nose that connects the bridge to the apex and is supported by the nasal bone

ear ossicles

three small bones located in the middle ear cavity that serve to transmit sound vibrations to the inner ear

early induced immune response

includes antimicrobial proteins stimulated during the first several days of an infection

eccentric contraction

muscle contraction that lengthens the muscle as the tension is diminished

eccrine sweat gland

type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation

ectoderm

outermost embryonic germ layer from which the epidermis and the nervous tissue derive

effector

organ that can cause a change in a value

effector T cells

immune cells with a direct, adverse effect on a pathogen

efferent lymphatic vessels

lead out of a lymph node

ejection fraction

portion of the blood that is pumped or ejected from the heart with each contraction; mathematically represented by SV divided by EDV

elastic artery

(also, conducting artery) artery with abundant elastic fibers located closer to the heart, which maintains the pressure gradient and conducts blood to smaller branches

elastic cartilage

type of cartilage, with elastin as the major protein, characterized by rigid support as well as elasticity

elastic fiber

fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size

elasticity

ability to stretch and rebound

elastin fibers

fibers made of the protein elastin that increase the elasticity of the dermis

elbow joint

joint located between the upper arm and forearm regions of the upper limb; formed by the articulations between the trochlea of the humerus and the trochlear notch of the ulna, and the capitulum of the humerus and the head of the radius

elbow joint

humeroulnar joint

electrocardiogram (ECG)

surface recording of the electrical activity of the heart that can be used for diagnosis of irregular heart function; also abbreviated as EKG

electron

subatomic particle having a negative charge and nearly no mass; found orbiting the atom’s nucleus

electron shell

area of space a given distance from an atom’s nucleus in which electrons are grouped

electrical gradient

difference in the electrical charge (potential) between two regions

eleiden

clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss

element

substance that cannot be created or broken down by ordinary chemical means

elevation

upward (superior) motion of the scapula or mandible

embolus

thrombus that has broken free from the blood vessel wall and entered the circulation

emigration

(also, diapedesis) process by which leukocytes squeeze through adjacent cells in a blood vessel wall to enter tissues

end diastolic volume (EDV)

(also, preload) the amount of blood in the ventricles at the end of atrial systole just prior to ventricular contraction

end systolic volume (ESV)

amount of blood remaining in each ventricle following systole

endocardium

innermost layer of the heart lining the heart chambers and heart valves; composed of endothelium reinforced with a thin layer of connective tissue that binds to the myocardium

endochondral ossification

process in which bone forms by replacing hyaline cartilage

endocytosis

import of material into the cell by formation of a membrane-bound vesicle

endoderm

innermost embryonic germ layer from which most of the digestive system and lower respiratory system derive

endomysium

loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle

endoplasmic reticulum (ER)

cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)

endosteum

delicate membranous lining of a bone’s medullary cavity

endothelium

layer of smooth, simple squamous epithelium that lines the endocardium and blood vessels

enzyme

protein or RNA that catalyzes chemical reactions

eosinophils

granulocytes that stain with eosin; they release antihistamines and are especially active against parasitic worms

epicardial coronary arteries

surface arteries of the heart that generally follow the sulci

epicardium

innermost layer of the serous pericardium and the outermost layer of the heart wall

epicranial aponeurosis

(also, galea aponeurosis) flat broad tendon that connects the frontalis and occipitalis

epidermis

outermost tissue layer of the skin

epiglottis

leaf-shaped piece of elastic cartilage that is a portion of the larynx that swings to close the trachea during swallowing

epimysium

outer layer of connective tissue around a skeletal muscle

epimysium

outer layer of connective tissue around a skeletal muscle

epiphyseal plate

(also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length

epiphyseal line

completely ossified remnant of the epiphyseal plate

epiphysis

wide section at each end of a long bone; filled with spongy bone and red marrow

epithelial membrane

epithelium attached to a layer of connective tissue

epithelial tissue

type of tissue that serves primarily as a covering or lining of body parts, protecting the body; it also functions in absorption, transport, and secretion

eponychium

nail fold that meets the proximal end of the nail body, also called the cuticle

erector spinae group

large muscle mass of the back; primary extensor of the vertebral column

erythroblastosis fetalis

disease of Rh factor-positive newborns in Rh-negative mothers with multiple Rh-positive children; resulting from the action of maternal antibodies against fetal blood

erythrocyte

(also, red blood cell) mature myeloid blood cell that is composed mostly of hemoglobin and functions primarily in the transportation of oxygen and carbon dioxide

erythropoietin (EPO)

glycoprotein that triggers the bone marrow to produce RBCs; secreted by the kidney in response to low oxygen levels

esophageal artery

branch of the thoracic aorta; supplies blood to the esophagus

esophageal vein

drains the inferior portions of the esophagus and leads to the azygos vein

ethmoid air cell

one of several small, air-filled spaces located within the lateral sides of the ethmoid bone, between the orbit and upper nasal cavity

ethmoid bone

unpaired bone that forms the roof and upper, lateral walls of the nasal cavity, portions of the floor of the anterior cranial fossa and medial wall of orbit, and the upper portion of the nasal septum

evaporation

transfer of heat that occurs when water changes from a liquid to a gas

eversion

foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned laterally, away from the midline

exchange reaction

type of chemical reaction in which bonds are both formed and broken, resulting in the transfer of components

excitability

ability to undergo neural stimulation

excitation-contraction coupling

sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres

excitation-contraction coupling

sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres

exocytosis

export of a substance out of a cell by formation of a membrane-bound vesicle

exon

one of the coding regions of an mRNA molecule that remain after splicing

expiration

(also, exhalation) process that causes the air to leave the lungs

expiratory reserve volume (ERV)

amount of air that can be forcefully exhaled after a normal tidal exhalation

extensibility

ability to lengthen (extend)

extension

movement in the sagittal plane that increases the angle of a joint (straightens the joint); motion involving posterior bending of the vertebral column or returning to the upright position from a flexed position

extensor

muscle that increases the angle at the joint

extensor carpi radialis brevis

muscle that extends and abducts the hand at the wrist

extensor carpi ulnaris

muscle that extends and adducts the hand

extensor digiti minimi

muscle that extends the little finger

extensor digitorum

muscle that extends the hand at the wrist and the phalanges

extensor digitorum brevis

muscle that extends the toes

extensor digitorum longus

muscle that is lateral to the tibialis anterior

extensor hallucis longus

muscle that is partly deep to the tibialis anterior and extensor digitorum longus

extensor indicis

muscle that inserts onto the tendon of the extensor digitorum of the index finger

extensor pollicis brevis

muscle that inserts onto the base of the proximal phalanx of the thumb

extensor pollicis longus

muscle that inserts onto the base of the distal phalanx of the thumb

extensor radialis longus

muscle that extends and abducts the hand at the wrist

extensor retinaculum

band of connective tissue that extends over the dorsal surface of the hand

external acoustic meatus

ear canal opening located on the lateral side of the skull

external callus

collar of hyaline cartilage and bone that forms around the outside of a fracture

external carotid artery

arises from the common carotid artery; supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx

external elastic membrane

membrane composed of elastic fibers that separates the tunica media from the tunica externa; seen in larger arteries

external iliac artery

branch of the common iliac artery that leaves the body cavity and becomes a femoral artery; supplies blood to the lower limbs

external iliac vein

formed when the femoral vein passes into the body cavity; drains the legs and leads to the common iliac vein

external intercostal

superficial intercostal muscles that raise the rib cage

external jugular vein

one of a pair of major veins located in the superficial neck region that drains blood from the more superficial portions of the head, scalp, and cranial regions, and leads to the subclavian vein

external nose

region of the nose that is easily visible to others

external oblique

superficial abdominal muscle with fascicles that extend inferiorly and medially

external occipital protuberance

small bump located at the midline on the posterior skull

external respiration

gas exchange that occurs in the alveoli

external root sheath

outer layer of the hair follicle that is an extension of the epidermis, which encloses the hair root

extracellular fluid (ECF)

fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body

extrinsic eye muscles

originate outside the eye and insert onto the outer surface of the white of the eye, and create eyeball movement

extrinsic pathway

initial coagulation pathway that begins with tissue damage and results in the activation of the common pathway

extrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate on the arm

facet

small, flattened area on a bone for an articulation (joint) with another bone, or for muscle attachment

facial bones

fourteen bones that support the facial structures and form the upper and lower jaws and the hard palate

facilitated diffusion

diffusion of a substance with the aid of a membrane protein

false ribs

vertebrochondral ribs 8–12 whose costal cartilage either attaches indirectly to the sternum via the costal cartilage of the next higher rib or does not attach to the sternum at all

fas ligand

molecule expressed on cytotoxic T cells and NK cells that binds to the fas molecule on a target cell and induces it do undergo apoptosis

fascicle

bundle of muscle fibers within a skeletal muscle

fascicle

muscle fibers bundled by perimysium into a unit

fauces

portion of the posterior oral cavity that connects the oral cavity to the oropharynx

Fc region

in an antibody molecule, the site where the two termini of the heavy chains come together; many cells have receptors for this portion of the antibody, adding functionality to these molecules

femoral artery

continuation of the external iliac artery after it passes through the body cavity; divides into several smaller branches, the lateral deep femoral artery, and the genicular artery; becomes the popliteal artery as it passes posterior to the knee

femoral circumflex vein

forms a loop around the femur just inferior to the trochanters; drains blood from the areas around the head and neck of the femur; leads to the femoral vein

femoral triangle

region formed at the junction between the hip and the leg and includes the pectineus, femoral nerve, femoral artery, femoral vein, and deep inguinal lymph nodes

femoral vein

drains the upper leg; receives blood from the great saphenous vein, the deep femoral vein, and the femoral circumflex vein; becomes the external iliac vein when it crosses the body wall

femoropatellar joint

portion of the knee joint consisting of the articulation between the distal femur and the patella

femur

thigh bone; the single bone of the thigh

fenestrated capillary

type of capillary with pores or fenestrations in the endothelium that allow for rapid passage of certain small materials

ferritin

protein-containing storage form of iron found in the bone marrow, liver, and spleen

fertilization

unification of genetic material from male and female haploid gametes

fertilization membrane

impenetrable barrier that coats a nascent zygote; part of the slow block to polyspermy

fibrin

insoluble, filamentous protein that forms the structure of a blood clot

fibrinogen

plasma protein produced in the liver and involved in blood clotting

fibrinolysis

gradual degradation of a blood clot

fibroblast

most abundant cell type in connective tissue, secretes protein fibers and matrix into the extracellular space

fibrocartilage

tough form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance

fibrocyte

less active form of fibroblast

fibroelastic membrane

specialized membrane that connects the ends of the C-shape cartilage in the trachea; contains smooth muscle fibers

fibrous joint

joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue

fibula

thin, non-weight-bearing bone found on the lateral side of the leg

fibular collateral ligament

extrinsic ligament of the knee joint that spans from the lateral epicondyle of the femur to the head of the fibula; resists hyperextension and rotation of the extended knee

fibular notch

wide groove on the lateral side of the distal tibia for articulation with the fibula at the distal tibiofibular joint

fibularis brevis

(also, peroneus brevis) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis longus

(also, peroneus longus) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis tertius

small muscle that is associated with the extensor digitorum longus

fibular vein

drains the muscles and integument near the fibula and leads to the popliteal vein

filling time

duration of ventricular diastole during which filling occurs

filtration

in the cardiovascular system, the movement of material from a capillary into the interstitial fluid, moving from an area of higher pressure to lower pressure

fixator

synergist that assists an agonist by preventing or reducing movement at another joint, thereby stabilizing the origin of the agonist

flagellum

appendage on certain cells formed by microtubules and modified for movement

flat bone

thin and curved bone; serves as a point of attachment for muscles and protects internal organs

flexion

movement in the sagittal plane that decreases the angle of a joint (bends the joint); motion involving anterior bending of the vertebral column

flexor

muscle that decreases the angle at the joint

flexor carpi radialis

muscle that flexes and abducts the hand at the wrist

flexor carpi ulnaris

muscle that flexes and adducts the hand at the wrist

flexor digiti minimi brevis

muscle that flexes the little finger

flexor digitorum longus

muscle that flexes the four small toes

flexor digitorum profundus

muscle that flexes the phalanges of the fingers and the hand at the wrist

flexor digitorum superficialis

muscle that flexes the hand and the digits

flexor hallucis longus

muscle that flexes the big toe

flexor pollicis brevis

muscle that flexes the thumb

flexor pollicis longus

muscle that flexes the distal phalanx of the thumb

flexor retinaculum

band of connective tissue that extends over the palmar surface of the hand

flexor retinaculum

strong band of connective tissue at the anterior wrist that spans the top of the U-shaped grouping of the carpal bones to form the roof of the carpal tunnel

floating ribs

vertebral ribs 11–12 that do not attach to the sternum or to the costal cartilage of another rib

fluid connective tissue

broad depression located on the posterio scapula, inferior to the spine specialized cells that circulate in a watery fluid containing salts, nutrients, and dissolved proteins

fontanelles

expanded areas of fibrous connective tissue that separate the braincase bones of the skull prior to birth and during the first year after birth

foot

portion of the lower limb located distal to the ankle joint

foramen lacerum

irregular opening in the base of the skull, located inferior to the exit of carotid canal

foramen ovale

opening in the fetal heart that allows blood to flow directly from the right atrium to the left atrium, bypassing the fetal pulmonary circuit

foramen magnum

large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium

foramen ovale of the middle cranial fossa

oval-shaped opening in the floor of the middle cranial fossa

foramen rotundum

round opening in the floor of the middle cranial fossa, located between the superior orbital fissure and foramen ovale

foramen spinosum

small opening in the floor of the middle cranial fossa, located lateral to the foramen ovale

forced breathing

(also, hyperpnea) mode of breathing that occurs during exercise or by active thought that requires muscle contraction for both inspiration and expiration

forearm

region of the upper limb located between the elbow and wrist joints; contains the radius and ulna bones

formed elements

cellular components of blood; that is, erythrocytes, leukocytes, and platelets

fossa

(plural = fossae) shallow depression on the surface of a bone

fovea capitis

minor indentation on the head of the femur that serves as the site of attachment for the ligament to the head of the femur

fossa ovalis

oval-shaped depression in the interatrial septum that marks the former location of the foramen ovale

fracture

broken bone

fracture hematoma

blood clot that forms at the site of a broken bone

Frank-Starling mechanism

relationship between ventricular stretch and contraction in which the force of heart contraction is directly proportional to the initial length of the muscle fiber

frontal bone

unpaired bone that forms forehead, roof of orbit, and floor of anterior cranial fossa

frontal sinus

air-filled space within the frontal bone; most anterior of the paranasal sinuses

frontal plane

two-dimensional, vertical plane that divides the body or organ into anterior and posterior portions

frontalis

front part of the occipitofrontalis muscle

functional group

group of atoms linked by strong covalent bonds that tends to behave as a distinct unit in chemical reactions with other atoms

functional residual capacity (FRC)

sum of ERV and RV, which is the amount of air that remains in the lungs after a tidal expiration

fusiform

muscle that has fascicles that are spindle-shaped to create large bellies

G₀ phase

phase of the cell cycle, usually entered from the G₁ phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase

G₁ phase

first phase of the cell cycle, after a new cell is born

G₂ phase

third phase of the cell cycle, after the DNA synthesis phase

gastrocnemius

most superficial muscle of the calf

gene

functional length of DNA that provides the genetic information necessary to build a protein

gene expression

active interpretation of the information coded in a gene to produce a functional gene product

genicular artery

branch of the femoral artery; supplies blood to the region of the knee

genioglossus

muscle that originates on the mandible and allows the tongue to move downward and forward

geniohyoid

muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly

genome

entire complement of an organism’s DNA; found within virtually every cell

germinal centers

clusters of rapidly proliferating B cells found in secondary lymphoid tissues

glabella

slight depression of frontal bone, located at the midline between the eyebrows

glassy membrane

layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis

glenohumeral joint

shoulder joint; articulation between the glenoid cavity of the scapula and head of the humerus; multiaxial ball-and-socket joint that allows for flexion/extension, abduction/adduction, circumduction, and medial/lateral rotation of the humerus

glenohumeral joint

shoulder joint; formed by the articulation between the glenoid cavity of the scapula and the head of the humerus

glenohumeral ligament

one of the three intrinsic ligaments of the shoulder joint that strengthen the anterior articular capsule

glenoid cavity

(also, glenoid fossa) shallow depression located on the lateral scapula, between the superior and lateral borders

glenoid labrum

lip of fibrocartilage located around the outside margin of the glenoid cavity of the scapula

globin

heme-containing globular protein that is a constituent of hemoglobin

globulins

heterogeneous group of plasma proteins that includes transport proteins, clotting factors, immune proteins, and others

glottis

opening between the vocal folds through which air passes when producing speech

gluteal group

muscle group that extends, flexes, rotates, adducts, and abducts the femur

gluteal tuberosity

roughened area on the posterior side of the proximal femur, extending inferiorly from the base of the greater trochanter

gluteus maximus

largest of the gluteus muscles that extends the femur

gluteus medius

muscle deep to the gluteus maximus that abducts the femur at the hip

gluteus minimus

smallest of the gluteal muscles and deep to the gluteus medius

glycocalyx

coating of sugar molecules that surrounds the cell membrane

glycolysis

anaerobic breakdown of glucose to ATP

glycoprotein

protein that has one or more carbohydrates attached

golgi apparatus

cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport

gomphosis

type of fibrous joint in which the root of a tooth is anchored into its bony jaw socket by strong periodontal ligaments

gonadal artery

branch of the abdominal aorta; supplies blood to the gonads or reproductive organs; also described as ovarian arteries or testicular arteries, depending upon the sex of the individual

gonadal vein

generic term for a vein draining a reproductive organ; may be either an ovarian vein or a testicular vein, depending on the sex of the individual

gracilis

muscle that adducts the thigh and flexes the leg at the knee

graded muscle response

modification of contraction strength

graft-versus-host disease

in bone marrow transplants; occurs when the transplanted cells mount an immune response against the recipient

granular leukocytes

leukocytes with abundant granules in their cytoplasm; specifically, neutrophils, eosinophils, and basophils

granzyme

apoptosis-inducing substance contained in granules of NK cells and cytotoxic T cells

great cardiac vein

vessel that follows the interventricular sulcus on the anterior surface of the heart and flows along the coronary sulcus into the coronary sinus on the posterior surface; parallels the anterior interventricular artery and drains the areas supplied by this vessel

great cerebral vein

receives most of the smaller vessels from the inferior cerebral veins and leads to the straight sinus

greater pelvis

(also, greater pelvic cavity or false pelvis) broad space above the pelvic brim defined laterally by the fan-like portion of the upper ilium

greater sciatic foramen

pelvic opening formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament

greater sciatic notch

large, U-shaped indentation located on the posterior margin of the ilium, superior to the ischial spine

greater trochanter

large, bony expansion of the femur that projects superiorly from the base of the femoral neck

greater tubercle

enlarged prominence located on the lateral side of the proximal humerus

greater wings of sphenoid bone

lateral projections of the sphenoid bone that form the anterior wall of the middle cranial fossa and an area of the lateral skull

great saphenous vein

prominent surface vessel located on the medial surface of the leg and thigh; drains the superficial portions of these areas and leads to the femoral vein

gross anatomy

study of the larger structures of the body, typically with the unaided eye; also referred to macroscopic anatomy

ground substance

fluid or semi-fluid portion of the matrix

growth
is the increase in body size. Humans, like all multicellular organisms, grow by increasing the number of existing cells, increasing the amount of non-cellular material around cells (such as mineral deposits in bone), and, within very narrow limits, increasing the size of existing cells.

hair

keratinous filament growing out of the epidermis

hair bulb

structure at the base of the hair root that surrounds the dermal papilla

hair follicle

cavity or sac from which hair originates

hair matrix

layer of basal cells from which a strand of hair grows

hair papilla

mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle

hair root

part of hair that is below the epidermis anchored to the follicle

hair shaft

part of hair that is above the epidermis but is not anchored to the follicle

Haldane effect

relationship between the partial pressure of oxygen and the affinity of hemoglobin for carbon dioxide

hallux

big toe; digit 1 of the foot

hamate

from the lateral side, the fourth of the four distal carpal bones; articulates with the lunate and triquetrum proximally, the fourth and fifth metacarpals distally, and the capitate laterally

hamstring group

three long muscles on the back of the leg

hand

region of the upper limb distal to the wrist joint

hard palate

bony structure that forms the roof of the mouth and floor of the nasal cavity, formed by the palatine process of the maxillary bones and the horizontal plate of the palatine bones

head of the femur

rounded, proximal end of the femur that articulates with the acetabulum of the hip bone to form the hip joint

head of the fibula

small, knob-like, proximal end of the fibula; articulates with the inferior aspect of the lateral condyle of the tibia

head of the humerus

smooth, rounded region on the medial side of the proximal humerus; articulates with the glenoid fossa of the scapula to form the glenohumeral (shoulder) joint

head of the metatarsal bone

expanded, distal end of each metatarsal bone

head of the radius

disc-shaped structure that forms the proximal end of the radius; articulates with the capitulum of the humerus as part of the elbow joint, and with the radial notch of the ulna as part of the proximal radioulnar joint

head of the rib

posterior end of a rib that articulates with the bodies of thoracic vertebrae

head of the ulna

small, rounded distal end of the ulna; articulates with the ulnar notch of the distal radius, forming the distal radioulnar joint

heart block

interruption in the normal conduction pathway

heart rate (HR)

number of times the heart contracts (beats) per minute

heart sounds

sounds heard via auscultation with a stethoscope of the closing of the atrioventricular valves (“lub”) and semilunar valves (“dub”)

heavy chain

larger protein chain of an antibody

helicase

enzyme that functions to separate the two DNA strands of a double helix during DNA replication

helper T cells (Th)

T cells that secrete cytokines to enhance other immune responses, involved in activation of both B and T cell lymphocytes

hematocrit

(also, packed cell volume) volume percentage of erythrocytes in a sample of centrifuged blood

hematopoiesis

production of blood cells, which occurs in the red marrow of the bones

heme

red, iron-containing pigment to which oxygen binds in hemoglobin

hemiazygos vein

smaller vein complementary to the azygos vein; drains the esophageal veins from the esophagus and the left intercostal veins, and leads to the brachiocephalic vein via the superior intercostal vein

hemocytoblast

hemopoietic stem cell that gives rise to the formed elements of blood

hemoglobin

oxygen-carrying compound in erythrocytes

hemolysis

destruction (lysis) of erythrocytes and the release of their hemoglobin into circulation

hemolytic disease of the newborn (HDN)

(also, erythroblastosis fetalis) disorder causing agglutination and hemolysis in an Rh⁺ fetus or newborn of an Rh⁻ mother

hemophilia

genetic disorder characterized by inadequate synthesis of clotting factors

hemopoiesis

production of the formed elements of blood

hemopoietic growth factors

chemical signals including erythropoietin, thrombopoietin, colony-stimulating factors, and interleukins that regulate the differentiation and proliferation of particular blood progenitor cells

hemopoietic stem cell

type of pluripotent stem cell that gives rise to the formed elements of blood (hemocytoblast)

hemorrhage

excessive bleeding

hemosiderin

protein-containing storage form of iron found in the bone marrow, liver, and spleen

hemostasis

physiological process by which bleeding ceases

Henry’s law

statement of the principle that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas

heparin

short-acting anticoagulant stored in mast cells and released when tissues are injured, opposes prothrombin

hepatic artery proper

branch of the common hepatic artery; supplies systemic blood to the liver

hepatic portal system

specialized circulatory pathway that carries blood from digestive organs to the liver for processing before being sent to the systemic circulation

hepatic vein

drains systemic blood from the liver and flows into the inferior vena cava

high endothelial venules

vessels containing unique endothelial cells specialized to allow migration of lymphocytes from the blood to the lymph node

hilum

concave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung

hip bone

coxal bone; single bone that forms the pelvic girdle; consists of three areas, the ilium, ischium, and pubis

hip joint

joint located at the proximal end of the lower limb; formed by the articulation between the acetabulum of the hip bone and the head of the femur

histamine

vasoactive mediator in granules of mast cells and is the primary cause of allergies and anaphylactic shock

histology

microscopic study of tissue architecture, organization, and function

histone

family of proteins that associate with DNA in the nucleus to form chromatin

hole

opening or depression in a bone

homeostasis

steady state of body systems that living organisms maintain

homologous

describes two copies of the same chromosome (not identical), one inherited from each parent

horizontal plate

medial extension from the palatine bone that forms the posterior quarter of the hard palate

hook of the hamate bone

bony extension located on the anterior side of the hamate carpal bone

humeroradial joint

articulation between the capitulum of the humerus and head of the radius

humeroulnar joint

articulation between the trochlea of humerus and the trochlear notch of the ulna; uniaxial hinge joint that allows for flexion/extension of the forearm

humerus

single bone of the upper arm

hyaline cartilage

most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance

hydrogen bond

dipole-dipole bond in which a hydrogen atom covalently bonded to an electronegative atom is weakly attracted to a second electronegative atom

hydrophilic

describes a substance or structure attracted to water

hydrophobic

describes a substance or structure repelled by water

hyoglossus

muscle that originates on the hyoid bone to move the tongue downward and flatten it

hyoid bone

small, U-shaped bone located in upper neck that does not contact any other bone

hyperextension

excessive extension of joint, beyond the normal range of movement

hyperflexion

excessive flexion of joint, beyond the normal range of movement

hyperpnea

increased rate and depth of ventilation due to an increase in oxygen demand that does not significantly alter blood oxygen or carbon dioxide levels

hypertension

chronic and persistent blood pressure measurements of 140/90 mm Hg or above

hypertonia

abnormally high muscle tone

hypertonic

describes a solution concentration that is higher than a reference concentration

hypodermis

connective tissue connecting the integument to the underlying bone and muscle

hypoglossal canal

paired openings that pass anteriorly from the anterior-lateral margins of the foramen magnum deep to the occipital condyles

hypophyseal (pituitary) fossa

shallow depression on top of the sella turcica that houses the pituitary (hypophyseal) gland

hypotonic

describes a solution concentration that is lower than a reference concentration

hypertrophic cardiomyopathy

pathological enlargement of the heart, generally for no known reason

hypertrophy

addition of structural proteins to muscle fibers

hyperventilation

increased ventilation rate that leads to abnormally low blood carbon dioxide levels and high (alkaline) blood pH

hypervolemia

abnormally high levels of fluid and blood within the body

hyponychium

thickened layer of stratum corneum that lies below the free edge of the nail

hypotonia

abnormally low muscle tone caused by the absence of low-level contractions

hypovolemia

abnormally low levels of fluid and blood within the body

hypovolemic shock

type of circulatory shock caused by excessive loss of blood volume due to hemorrhage or possibly dehydration

hypoxemia

below-normal level of oxygen saturation of blood (typically <95 percent)

hypoxia

lack of oxygen supply to the tissues

hypothenar

group of muscles on the medial aspect of the palm

hypothenar eminence

rounded contour of muscle at the base of the little finger

IgA

antibody whose dimer is secreted by exocrine glands, is especially effective against digestive and respiratory pathogens, and can pass immunity to an infant through breastfeeding

IgD

class of antibody whose only known function is as a receptor on naive B cells; important in B cell activation

IgE

antibody that binds to mast cells and causes antigen-specific degranulation during an allergic response

IgG

main blood antibody of late primary and early secondary responses; passed from mother to unborn child via placenta

IgM

antibody whose monomer is a surface receptor of naive B cells; the pentamer is the first antibody made blood plasma during primary responses

immune system

series of barriers, cells, and soluble mediators that combine to response to infections of the body with pathogenic organisms

immunoglobulin

protein antibody; occurs as one of five main classes

inferior pubic ramus

narrow segment of bone that passes inferiorly and laterally from the pubic body; joins with the ischial ramus to form the ischiopubic ramus

inferior rotation

movement of the scapula during upper limb adduction in which the glenoid cavity of the scapula moves in a downward direction as the medial end of the scapular spine moves in an upward direction

inferior vena cava

large systemic vein that returns blood to the heart from the inferior portion of the body

inflammation

basic innate immune response characterized by heat, redness, pain, and swelling

infraglenoid tubercle

small bump or roughened area located on the lateral border of the scapula, near the inferior margin of the glenoid cavity

infrahyoid muscles

anterior neck muscles that are attached to, and inferior to the hyoid bone

infraspinatus

muscle that laterally rotates the arm

innate immune response

rapid but relatively nonspecific immune response

internal respiration

gas exchange that occurs at the level of body tissues

iliac crest

curved, superior margin of the ilium

iliac fossa

shallow depression found on the anterior and medial surfaces of the upper ilium

iliacus

muscle that, along with the psoas major, makes up the iliopsoas

iliococcygeus

muscle that makes up the levator ani along with the pubococcygeus

iliocostalis cervicis

muscle of the iliocostalis group associated with the cervical region

iliocostalis group

laterally placed muscles of the erector spinae

iliocostalis lumborum

muscle of the iliocostalis group associated with the lumbar region

iliocostalis thoracis

muscle of the iliocostalis group associated with the thoracic region

iliofemoral ligament

intrinsic ligament spanning from the ilium of the hip bone to the femur, on the superior-anterior aspect of the hip joint

iliopsoas group

muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip

iliotibial tract

muscle that inserts onto the tibia; made up of the gluteus maximus and connective tissues of the tensor fasciae latae

ilium

superior portion of the hip bone

immunoglobulins

(also, antibodies or gamma globulins) antigen-specific proteins produced by specialized B lymphocytes that protect the body by binding to foreign objects such as bacteria and viruses

immunological memory

ability of the adaptive immune response to mount a stronger and faster immune response upon re-exposure to a pathogen

inferior

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as caudal

inferior angle of the scapula

inferior corner of the scapula located where the medial and lateral borders meet

inferior articular process

bony process that extends downward from the vertebral arch of a vertebra that articulates with the superior articular process of the next lower vertebra

inferior extensor retinaculum

cruciate ligament of the ankle

inferior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

inferior mesenteric artery

branch of the abdominal aorta; supplies blood to the distal segment of the large intestine and rectum

inferior nasal concha

one of the paired bones that project from the lateral walls of the nasal cavity to form the largest and most inferior of the nasal conchae

inferior phrenic artery

branch of the abdominal aorta; supplies blood to the inferior surface of the diaphragm

inferior vena cava

large systemic vein that drains blood from areas largely inferior to the diaphragm; empties into the right atrium

infraorbital foramen

opening located on anterior skull, below the orbit

infraspinous fossa

broad depression located on the posterior scapula, inferior to the spine

infratemporal fossa

space on lateral side of skull, below the level of the zygomatic arch and deep (medial) to the ramus of the mandible

innermost intercostal

the deepest intercostal muscles that draw the ribs together

inorganic compound

substance that does not contain both carbon and hydrogen

insertion

end of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts

inspiration

(also, inhalation) process that causes air to enter the lungs

inspiratory capacity (IC)

sum of the TV and IRV, which is the amount of air that can maximally be inhaled past a tidal expiration

inspiratory reserve volume (IRV)

amount of air that enters the lungs due to deep inhalation past the tidal volume

integral protein

membrane-associated protein that spans the entire width of the lipid bilayer

integumentary system

skin and its accessory structures

interatrial band

(also, Bachmann’s bundle) group of specialized conducting cells that transmit the impulse directly from the SA node in the right atrium to the left atrium

internal acoustic meatus

opening into petrous ridge, located on the lateral wall of the posterior cranial fossa

interatrial septum

cardiac septum located between the two atria; contains the fossa ovalis after birth

intercalated disc

physical junction between adjacent cardiac muscle cells; consisting of desmosomes, specialized linking proteoglycans, and gap junctions that allow passage of ions between the two cells

intercondylar eminence

irregular elevation on the superior end of the tibia, between the articulating surfaces of the medial and lateral condyles

intercondylar fossa

deep depression on the posterior side of the distal femur that separates the medial and lateral condyles

intercostal artery

branch of the thoracic aorta; supplies blood to the muscles of the thoracic cavity and vertebral column

intercostal muscles

muscles that span the spaces between the ribs

intercostal vein

drains the muscles of the thoracic wall and leads to the azygos vein

interferons

early induced proteins made in virally infected cells that cause nearby cells to make antiviral proteins

intermediate cuneiform

middle of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the medial cuneiform bone, laterally with the lateral cuneiform bone, and anteriorly with the second metatarsal bone

intermediate filament

type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension

internal intercostal

muscles the intermediate intercostal muscles that draw the ribs together

internal jugular vein

one of a pair of major veins located in the neck region that passes through the jugular foramen and canal, flows parallel to the common carotid artery that is more or less its counterpart; primarily drains blood from the brain, receives the superficial facial vein, and empties into the subclavian vein

internal oblique

flat, intermediate abdominal muscle with fascicles that run perpendicular to those of the external oblique

internal thoracic artery

(also, mammary artery) arises from the subclavian artery; supplies blood to the thymus, pericardium of the heart, and the anterior chest wall

internal thoracic vein

(also, internal mammary vein) drains the anterior surface of the chest wall and leads to the brachiocephalic vein

interosseous border of the fibula

small ridge running down the medial side of the fibular shaft; for attachment of the interosseous membrane between the fibula and tibia

interosseous border of the radius

narrow ridge located on the medial side of the radial shaft; for attachment of the interosseous membrane between the ulna and radius bones

interosseous border of the tibia

small ridge running down the lateral side of the tibial shaft; for attachment of the interosseous membrane between the tibia and fibula

interosseous border of the ulna

narrow ridge located on the lateral side of the ulnar shaft; for attachment of the interosseous membrane between the ulna and radius

interosseous membrane

wide sheet of fibrous connective tissue that fills the gap between two parallel bones, forming a syndesmosis; found between the radius and ulna of the forearm and between the tibia and fibula of the leg

interosseous membrane of the forearm

sheet of dense connective tissue that unites the radius and ulna bones

interosseous membrane of the leg

sheet of dense connective tissue that unites the shafts of the tibia and fibula bones

interphalangeal joint

articulation between adjacent phalanx bones of the hand or foot digits

interphase

entire life cycle of a cell, excluding mitosis

interstitial fluid colloidal osmotic pressure (IFCOP)

pressure exerted by the colloids within the interstitial fluid

interstitial fluid hydrostatic pressure (IFHP)

force exerted by the fluid in the tissue spaces

intertrochanteric crest

short, prominent ridge running between the greater and lesser trochanters on the posterior side of the proximal femur

intertrochanteric line

small ridge running between the greater and lesser trochanters on the anterior side of the proximal femur

intertubercular groove (sulcus)

bicipital groove; narrow groove located between the greater and lesser tubercles of the humerus

intervertebral disc

structure located between the bodies of adjacent vertebrae that strongly joins the vertebrae; provides padding, weight bearing ability, and enables vertebral column movements

intervertebral foramen

opening located between adjacent vertebrae for exit of a spinal nerve

interleukins

signaling molecules that may function in hemopoiesis, inflammation, and specific immune responses

intermediate

group of midpalmar muscles

internal elastic membrane

membrane composed of elastic fibers that separates the tunica intima from the tunica media; seen in larger arteries

internal root sheath

innermost layer of keratinocytes in the hair follicle that surround the hair root up to the hair shaft

internodal pathways

specialized conductile cells within the atria that transmit the impulse from the SA node throughout the myocardial cells of the atrium and to the AV node

interventricular septum

cardiac septum located between the two ventricles

interstitial fluid (IF)

fluid in the small spaces between cells not contained within blood vessels

intra-alveolar pressure

(intrapulmonary pressure) pressure of the air within the alveoli

intracellular fluid (ICF)

fluid in the cytosol of cells

intramembranous ossification

process by which bone forms directly from mesenchymal tissue

intrapleural pressure

pressure of the air within the pleural cavity

intrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate in the palm

intrinsic pathway

initial coagulation pathway that begins with vascular damage or contact with foreign substances, and results in the activation of the common pathway

intron

non-coding regions of a pre-mRNA transcript that may be removed during splicing

inversion

foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned toward the midline

ion

atom with an overall positive or negative charge

ionic bond

attraction between an anion and a cation

irregular bone

bone of complex shape; protects internal organs from compressive forces

ischemia

insufficient blood flow to the tissues

ischial ramus

bony extension projecting anteriorly and superiorly from the ischial tuberosity; joins with the inferior pubic ramus to form the ischiopubic ramus

ischial spine

pointed, bony projection from the posterior margin of the ischium that separates the greater sciatic notch and lesser sciatic notch

ischial tuberosity

large, roughened protuberance that forms the posteroinferior portion of the hip bone; weight-bearing region of the pelvis when sitting

ischiococcygeus

muscle that assists the levator ani and pulls the coccyx anteriorly

ischiofemoral ligament

intrinsic ligament spanning from the ischium of the hip bone to the femur, on the posterior aspect of the hip joint

ischiopubic ramus

narrow extension of bone that connects the ischial tuberosity to the pubic body; formed by the junction of the ischial ramus and inferior pubic ramus

ischium

posteroinferior portion of the hip bone

isometric contraction

muscle contraction that occurs with no change in muscle length

isotonic

describes a solution concentration that is the same as a reference concentration

isotonic contraction

muscle contraction that involves changes in muscle length

isotope

one of the variations of an element in which the number of neutrons differ from each other

isovolumic contraction

(also, isovolumetric contraction) initial phase of ventricular contraction in which tension and pressure in the ventricle increase, but no blood is pumped or ejected from the heart

isovolumic ventricular relaxation phase

initial phase of the ventricular diastole when pressure in the ventricles drops below pressure in the two major arteries, the pulmonary trunk, and the aorta, and blood attempts to flow back into the ventricles, producing the dicrotic notch of the ECG and closing the two semilunar valves

joint

site at which two or more bones or bone and cartilage come together (articulate)

joint cavity

space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones

jugular foramen

irregularly shaped opening located in the lateral floor of the posterior cranial cavity

jugular (suprasternal) notch

shallow notch located on superior surface of sternal manubrium

keratin

type of structural protein that gives skin, hair, and nails its hard, water-resistant properties

keratinocyte

cell that produces keratin and is the most predominant type of cell found in the epidermis

keratohyalin

granulated protein found in the stratum granulosum

kinetic energy

energy that matter possesses because of its motion

kinetochore

region of a centromere where microtubules attach to a pair of sister chromatids

knee joint

joint that separates the thigh and leg portions of the lower limb; formed by the articulations between the medial and lateral condyles of the femur, and the medial and lateral condyles of the tibia

Korotkoff sounds

noises created by turbulent blood flow through the vessels

kyphosis

(also, humpback or hunchback) excessive posterior curvature of the thoracic vertebral column region

lacrimal bone

paired bones that contribute to the anterior-medial wall of each orbit

lacrimal fossa

shallow depression in the anterior-medial wall of the orbit, formed by the lacrimal bone that gives rise to the nasolacrimal canal

lactic acid

product of anaerobic glycolysis

lacunae

(singular = lacuna) small spaces in bone or cartilage tissue that cells occupy

lacunae

(singular = lacuna) spaces in a bone that house an osteocyte

lambdoid suture

inverted V-shaped joint that unites the occipital bone to the right and left parietal bones on the posterior skull

lamina

portion of the vertebral arch on each vertebra that extends between the transverse and spinous process

lamina propria

areolar connective tissue underlying a mucous membrane

Langerhans cell

specialized dendritic cell found in the stratum spinosum that functions as a macrophage

laryngeal prominence

region where the two lamina of the thyroid cartilage join, forming a protrusion known as “Adam’s apple”

laryngopharynx

portion of the pharynx bordered by the oropharynx superiorly and esophagus and trachea inferiorly; serves as a route for both air and food

larynx

cartilaginous structure that produces the voice, prevents food and beverages from entering the trachea, and regulates the volume of air that enters and leaves the lungs

latent period

the time when a twitch does not produce contraction

lateral

describes the side or direction toward the side of the body

lateral border of the scapula

diagonally oriented lateral margin of the scapula

lateral circumflex artery

branch of the deep femoral artery; supplies blood to the deep muscles of the thigh and the ventral and lateral regions of the integument

lateral compartment of the leg

region that includes the fibularis (peroneus) longus and the fibularis (peroneus) brevis and their associated blood vessels and nerves

lateral condyle of the femur

smooth, articulating surface that forms the distal and posterior sides of the lateral expansion of the distal femur

lateral condyle of the tibia

lateral, expanded region of the proximal tibia that includes the smooth surface that articulates with the lateral condyle of the femur as part of the knee joint

lateral cuneiform

most lateral of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the intermediate cuneiform bone, laterally with the cuboid bone, and anteriorly with the third metatarsal bone

lateral epicondyle of the femur

roughened area of the femur located on the lateral side of the lateral condyle

lateral epicondyle of the humerus

small projection located on the lateral side of the distal humerus

lateral excursion

side-to-side movement of the mandible away from the midline, toward either the right or left side

lateral flexion

bending of the neck or body toward the right or left side

lateral meniscus

C-shaped fibrocartilage articular disc located at the knee, between the lateral condyle of the femur and the lateral condyle of the tibia

lateral plantar artery

arises from the bifurcation of the posterior tibial arteries; supplies blood to the lateral plantar surfaces of the foot

lateral pterygoid

muscle that moves the mandible from side to side

lateral pterygoid plate

paired, flattened bony projections of the sphenoid bone located on the inferior skull, lateral to the medial pterygoid plate

lateralis

to the outside

lateral malleolus

expanded distal end of the fibula

lateral sacral crest

paired irregular ridges running down the lateral sides of the posterior sacrum that was formed by the fusion of the transverse processes from the five sacral vertebrae

lateral supracondylar ridge

narrow, bony ridge located along the lateral side of the distal humerus, superior to the lateral epicondyle

lateral tibiofemoral joint

portion of the knee consisting of the articulation between the lateral condyle of the tibia and the lateral condyle of the femur; allows for flexion/extension at the knee

lateral (external) rotation

movement of the arm at the shoulder joint or the thigh at the hip joint that moves the anterior surface of the limb away from the midline of the body

latissimus dorsi

broad, triangular axial muscle located on the inferior part of the back

left atrioventricular valve

(also, mitral valve or bicuspid valve) valve located between the left atrium and ventricle; consists of two flaps of tissue

left gastric artery

branch of the celiac trunk; supplies blood to the stomach

leg

portion of the lower limb located between the knee and ankle joints

lesser pelvis

(also, lesser pelvic cavity or true pelvis) narrow space located within the pelvis, defined superiorly by the pelvic brim (pelvic inlet) and inferiorly by the pelvic outlet

lesser sciatic foramen

pelvic opening formed by the lesser sciatic notch of the hip bone, the sacrospinous ligament, and the sacrotuberous ligament

lesser sciatic notch

shallow indentation along the posterior margin of the ischium, inferior to the ischial spine

lesser trochanter

small, bony projection on the medial side of the proximal femur, at the base of the femoral neck

lesser tubercle

small, bony prominence located on anterior side of the proximal humerus

lesser wings of the sphenoid bone

lateral extensions of the sphenoid bone that form the bony lip separating the anterior and middle cranial fossae

leukemia

cancer involving leukocytes

leukocyte

(also, white blood cell) colorless, nucleated blood cell, the chief function of which is to protect the body from disease

leukocytosis

excessive leukocyte proliferation

leukopenia

below-normal production of leukocytes

levator ani

pelvic muscle that resists intra-abdominal pressure and supports the pelvic viscera

ligament

strong band of dense connective tissue spanning between bones

ligament of the head of the femur

ligament that spans the acetabulum of the hip bone and the fovea capitis of the femoral head

ligament of the head of the femur

intracapsular ligament that runs from the acetabulum of the hip bone to the head of the femur

ligamentum flavum

series of short ligaments that unite the lamina of adjacent vertebrae

ligand

molecule that binds with specificity to a specific receptor molecule

light chain

small protein chain of an antibody

limb bud

small elevation that appears on the lateral side of the embryo during the fourth or fifth week of development, which gives rise to an upper or lower limb

linea alba

white, fibrous band that runs along the midline of the trunk

linea aspera

longitudinally running bony ridge located in the middle third of the posterior femur

lingual tonsil

lymphoid tissue located at the base of the tongue

lingula

small flap of bone located on the inner (medial) surface of mandibular ramus, next to the mandibular foramen

lipid

class of nonpolar organic compounds built from hydrocarbons and distinguished by the fact that they are not soluble in water

long bone

cylinder-shaped bone that is longer than it is wide; functions as a lever

longissimus capitis

muscle of the longissimus group associated with the head region

longissimus cervicis

muscle of the longissimus group associated with the cervical region

longissimus group

intermediately placed muscles of the erector spinae

longissimus thoracis

muscle of the longissimus group associated with the thoracic region

longus

long

loose connective tissue

(also, areolar tissue) type of connective tissue proper that shows little specialization with cells dispersed in the matrix

lordosis

(also, swayback) excessive anterior curvature of the lumbar vertebral column region

lumbar arteries

branches of the abdominal aorta; supply blood to the lumbar region, the abdominal wall, and spinal cord

lumbar curve

posteriorly concave curvature of the lumbar vertebral column region; a secondary curve of the vertebral column

lumbar veins

drain the lumbar portion of the abdominal wall and spinal cord; the superior lumbar veins drain into the azygos vein on the right or the hemiazygos vein on the left; blood from these vessels is returned to the superior vena cava rather than the inferior vena cava

lumbar vertebrae

five vertebrae numbered as L1–L5 that are located in lumbar region (lower back) of the vertebral column

lumbrical

muscle that flexes each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

lumen

interior of a tubular structure such as a blood vessel or a portion of the alimentary canal through which blood, chyme, or other substances travel

lunate

from the lateral side, the second of the four proximal carpal bones; articulates with the radius proximally, the capitate and hamate distally, the scaphoid laterally, and the triquetrum medially

lung

organ of the respiratory system that performs gas exchange

lunula

basal part of the nail body that consists of a crescent-shaped layer of thick epithelium

lymph

fluid contained within the lymphatic system

lymphatic capillaries

smallest of the lymphatic vessels and the origin of lymph flow

lymphatic system

network of lymphatic vessels, lymph nodes, and ducts that carries lymph from the tissues and back to the bloodstream.

lymphatic trunks

large lymphatics that collect lymph from smaller lymphatic vessels and empties into the blood via lymphatic ducts

lymph node

one of the bean-shaped organs found associated with the lymphatic vessels

lymphocytes

agranular leukocytes of the lymphoid stem cell line, many of which function in specific immunity

lymphocytes

white blood cells characterized by a large nucleus and small rim of cytoplasm

lymphoid nodules

unencapsulated patches of lymphoid tissue found throughout the body

lymphoid stem cells

type of hemopoietic stem cells that gives rise to lymphocytes, including various T cells, B cells, and NK cells, all of which function in immunity

lymphoma

form of cancer in which masses of malignant T and/or B lymphocytes collect in lymph nodes, the spleen, the liver, and other tissues

lysosome

membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes

lysozyme

digestive enzyme with bactericidal properties

macromolecule

large molecule formed by covalent bonding

macrophage

phagocytic cell of the myeloid lineage; a matured monocyte

macrophage

ameboid phagocyte found in several tissues throughout the body

macrophage oxidative metabolism

metabolism turned on in macrophages by T cell signals that help destroy intracellular bacteria

major histocompatibility complex (MHC)

gene cluster whose proteins present antigens to T cells

mandible

unpaired bone that forms the lower jaw bone; the only moveable bone of the skull

mandibular foramen

opening located on the inner (medial) surface of the mandibular ramus

mandibular fossa

oval depression located on the inferior surface of the skull

mandibular notch

large U-shaped notch located between the condylar process and coronoid process of the mandible

manubrium

expanded, superior portion of the sternum

masseter

main muscle for chewing that elevates the mandible to close the mouth

mass number

sum of the number of protons and neutrons in the nucleus of an atom

mastication

chewing

mastoid process

large bony prominence on the inferior, lateral skull, just behind the earlobe

marginal arteries

branches of the right coronary artery that supply blood to the superficial portions of the right ventricle

matrix

extracellular material which is produced by the cells embedded in it, containing ground substance and fibers

mast cell

cell found in the skin and the lining of body cells that contains cytoplasmic granules with vasoactive mediators such as histamine

matter

physical substance; that which occupies space and has mass

maxillary bone

(also, maxilla) paired bones that form the upper jaw and anterior portion of the hard palate

maxillary sinus

air-filled space located with each maxillary bone; largest of the paranasal sinuses

maxillary vein

drains blood from the maxillary region and leads to the external jugular vein

maximus

largest

mean arterial pressure (MAP)

average driving force of blood to the tissues; approximated by taking diastolic pressure and adding 1/3 of pulse pressure

meatus

one of three recesses (superior, middle, and inferior) in the nasal cavity attached to the conchae that increase the surface area of the nasal cavity

medial

describes the middle or direction toward the middle of the body

medial border of the scapula

elongated, medial margin of the scapula

medial compartment of the thigh

a region that includes the adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and their associated blood vessels and nerves

medial condyle of the femur

smooth, articulating surface that forms the distal and posterior sides of the medial expansion of the distal femur

medial condyle of the tibia

medial, expanded region of the proximal tibia that includes the smooth surface that articulates with the medial condyle of the femur as part of the knee joint

medial cuneiform

most medial of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, laterally with the intermediate cuneiform bone, and anteriorly with the first and second metatarsal bones

medial epicondyle of the femur

roughened area of the distal femur located on the medial side of the medial condyle

medial epicondyle of the humerus

enlarged projection located on the medial side of the distal humerus

medial excursion

side-to-side movement that returns the mandible to the midline

medialis

to the inside

medial malleolus

bony expansion located on the medial side of the distal tibia

medial meniscus

C-shaped fibrocartilage articular disc located at the knee, between the medial condyle of the femur and medial condyle of the tibia

medial plantar artery

arises from the bifurcation of the posterior tibial arteries; supplies blood to the medial plantar surfaces of the foot

medial pterygoid

muscle that moves the mandible from side to side

medial pterygoid plate

paired, flattened bony projections of the sphenoid bone located on the inferior skull medial to the lateral pterygoid plate; form the posterior portion of the nasal cavity lateral wall

medial (internal) rotation

movement of the arm at the shoulder joint or the thigh at the hip joint that brings the anterior surface of the limb toward the midline of the body

medial tibiofemoral joint

portion of the knee consisting of the articulation between the medial condyle of the tibia and the medial condyle of the femur; allows for flexion/extension at the knee

median antebrachial vein

vein that parallels the ulnar vein but is more medial in location; intertwines with the palmar venous arches

median cubital vein

superficial vessel located in the antecubital region that links the cephalic vein to the basilic vein in the form of a v; a frequent site for a blood draw

median sacral artery

continuation of the aorta into the sacrum

median sacral crest

irregular ridge running down the midline of the posterior sacrum that was formed from the fusion of the spinous processes of the five sacral vertebrae

mediastinal artery

branch of the thoracic aorta; supplies blood to the mediastinum

medius

medium

medulla

in hair, the innermost layer of keratinocytes originating from the hair matrix

medullary cavity

hollow region of the diaphysis; filled with yellow marrow

megakaryocyte

bone marrow cell that produces platelets

Meissner corpuscle

(also, tactile corpuscle) receptor in the skin that responds to light touch

melanin

pigment that determines the color of hair and skin

melanocyte

cell found in the stratum basale of the epidermis that produces the pigment melanin

melanosome

intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis

memory cell

type of B or T lymphocyte that forms after exposure to a pathogen

memory T cells

long-lived immune cell reserved for future exposure to an pathogen

mental foramen

opening located on the anterior-lateral side of the mandibular body

mental protuberance

inferior margin of anterior mandible that forms the chin

Merkel cell

receptor cell in the stratum basale of the epidermis that responds to the sense of touch

mesenchymal cell

adult stem cell from which most connective tissue cells are derived

mesenchyme

embryonic tissue from which connective tissue cells derive

mesoderm

middle embryonic germ layer from which connective tissue, muscle tissue, and some epithelial tissue derive

mesothelium

simple squamous epithelial portion of serous membranes, such as the superficial portion of the epicardium (the visceral pericardium) and the deepest portion of the pericardium (the parietal pericardium)

messenger RNA (mRNA)

nucleotide molecule that serves as an intermediate in the genetic code between DNA and protein

metabolic rate

amount of energy consumed minus the amount of energy expended by the body

metacarpal bone

one of the five long bones that form the palm of the hand; numbered 1–5, starting on the lateral (thumb) side of the hand

metacarpophalangeal joint

articulation between the distal end of a metacarpal bone of the hand and a proximal phalanx bone of the thumb or a finger

metaphase

second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell

metaphase plate

linear alignment of sister chromatids in the center of the cell, which takes place during metaphase

metatarsal bone

one of the five elongated bones that forms the anterior half of the foot; numbered 1–5, starting on the medial side of the foot

metatarsophalangeal joint

articulation between a metatarsal bone of the foot and the proximal phalanx bone of a toe

metarteriole

short vessel arising from a terminal arteriole that branches to supply a capillary bed

MHC class I

found on most cells of the body, it binds to the CD8 molecule on T cells

MHC class II

found on macrophages, dendritic cells, and B cells, it binds to CD4 molecules on T cells

MHC polygeny

multiple MHC genes and their proteins found in body cells

MHC polymorphism

multiple alleles for each individual MHC locus

microcirculation

blood flow through the capillaries

microfilament

the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support

microscopic anatomy

study of very small structures of the body using magnification

microtubule

the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support

midcarpal joint

articulation between the proximal and distal rows of the carpal bones; contributes to movements of the hand at the wrist

middle cardiac vein

vessel that parallels and drains the areas supplied by the posterior interventricular artery; drains into the great cardiac vein

middle cerebral artery

another branch of the internal carotid artery; supplies blood to the temporal and parietal lobes of the cerebrum

middle cranial fossa

centrally located cranial fossa that extends from the lesser wings of the sphenoid bone to the petrous ridge

middle nasal concha

nasal concha formed by the ethmoid bone that is located between the superior and inferior conchae

middle sacral vein

drains the sacral region and leads to the left common iliac vein

middle scalene

longest scalene muscle, located between the anterior and posterior scalenes

minimus

smallest

mitochondrion

one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP)

mitosis

division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed

mitotic phase

phase of the cell cycle in which a cell undergoes mitosis

mitotic spindle

network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis

mitral valve

(also, left atrioventricular valve or bicuspid valve) valve located between the left atrium and ventricle; consists of two flaps of tissue

modeling

process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another

moderator band

band of myocardium covered by endocardium that arises from the inferior portion of the interventricular septum in the right ventricle and crosses to the anterior papillary muscle; contains conductile fibers that carry electrical signals followed by contraction of the heart

molecule

two or more atoms covalently bonded together

monocyte

precursor to macrophages and dendritic cells seen in the blood

monocytes

agranular leukocytes of the myeloid stem cell line that circulate in the bloodstream; tissue monocytes are macrophages

monosaccharide

monomer of carbohydrate; also known as a simple sugar

motor end-plate

sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine

motor end-plate

sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine

motor unit

motor neuron and the group of muscle fibers it innervates

mucosa-associated lymphoid tissue (MALT)

lymphoid nodule associated with the mucosa

mucous connective tissue

specialized loose connective tissue present in the umbilical cord

mucous membrane

tissue membrane that is covered by protective mucous and lines tissue exposed to the outside environment

multiaxial joint

type of diarthrosis; a joint that allows for movements within three planes (three axes)

multifidus

muscle of the lumbar region that helps extend and laterally flex the vertebral column

multipennate

pennate muscle that has a tendon branching within it

murmur

unusual heart sound detected by auscultation; typically related to septal or valve defects

muscle tension

force generated by the contraction of the muscle; tension generated during isotonic contractions and isometric contractions

muscle tissue

type of tissue that is capable of contracting and generating tension in response to stimulation; produces movement.

muscle tone

low levels of muscle contraction that occur when a muscle is not producing movement

muscular artery

(also, distributing artery) artery with abundant smooth muscle in the tunica media that branches to distribute blood to the arteriole network

mutation

change in the nucleotide sequence in a gene within a cell’s DNA

myeloid stem cells

type of hemopoietic stem cell that gives rise to some formed elements, including erythrocytes, megakaryocytes that produce platelets, and a myeloblast lineage that gives rise to monocytes and three forms of granular leukocytes (neutrophils, eosinophils, and basophils)

myelin

layer of lipid inside some neuroglial cells that wraps around the axons of some neurons

mylohyoid

muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth

mylohyoid line

bony ridge located along the inner (medial) surface of the mandibular body

myocardium

thickest layer of the heart composed of cardiac muscle cells built upon a framework of primarily collagenous fibers and blood vessels that supply it and the nervous fibers that help to regulate it

myocardial conducting cells

specialized cells that transmit electrical impulses throughout the heart and trigger contraction by the myocardial contractile cells

myocardial contractile cells

bulk of the cardiac muscle cells in the atria and ventricles that conduct impulses and contract to propel blood

myocyte

muscle cells

myofibril

long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres

myogenic response

constriction or dilation in the walls of arterioles in response to pressures related to blood flow; reduces high blood flow or increases low blood flow to help maintain consistent flow to the capillary network

myogram

instrument used to measure twitch tension

myosin

protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber

nail bed

layer of epidermis upon which the nail body forms

nail body

main keratinous plate that forms the nail

nail cuticle

fold of epithelium that extends over the nail bed, also called the eponychium

nail fold

fold of epithelium at that extend over the sides of the nail body, holding it in place

nail root

part of the nail that is lodged deep in the epidermis from which the nail grows

naïve lymphocyte

mature B or T cell that has not yet encountered antigen for the first time

naris

(plural = nares) opening of the nostrils

nasal bone

bone of the skull that lies under the root and bridge of the nose and is connected to the frontal and maxillary bones

nasal bone

paired bones that form the base of the nose

nasal cavity

opening through skull for passage of air

nasal conchae

curved bony plates that project from the lateral walls of the nasal cavity; include the superior and middle nasal conchae, which are parts of the ethmoid bone, and the independent inferior nasal conchae bone

nasal septum

flat, midline structure that divides the nasal cavity into halves, formed by the perpendicular plate of the ethmoid bone, vomer bone, and septal cartilage

nasal septum

wall composed of bone and cartilage that separates the left and right nasal cavities

nasolacrimal canal

passage for drainage of tears that extends downward from the medial-anterior orbit to the nasal cavity, terminating behind the inferior nasal conchae

nasopharynx

portion of the pharynx flanked by the conchae and oropharynx that serves as an airway

natural killer (NK) cells

cytotoxic lymphocytes capable of recognizing cells that do not express “self” proteins on their plasma membrane or that contain foreign or abnormal markers; provide generalized, nonspecific immunity

natural killer cell (NK)

cytotoxic lymphocyte of innate immune response

navicular

tarsal bone that articulates posteriorly with the talus bone, laterally with the cuboid bone, and anteriorly with the medial, intermediate, and lateral cuneiform bones

neck of the femur

narrowed region located inferior to the head of the femur

neck of the radius

narrowed region immediately distal to the head of the radius

neck of the rib

narrowed region of a rib, next to the rib head

negative feedback

homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removed

negative inotropic factors

factors that negatively impact or lower heart contractility

negative selection

selection against thymocytes in the thymus that react with self-antigen

nervi vasorum

small nerve fibers found in arteries and veins that trigger contraction of the smooth muscle in their walls

nervous tissue

type of tissue that is capable of sending and receiving impulses through electrochemical signals.

net filtration pressure (NFP)

force driving fluid out of the capillary and into the tissue spaces; equal to the difference of the capillary hydrostatic pressure and the blood colloidal osmotic pressure

neurogenic shock

type of shock that occurs with cranial or high spinal injuries that damage the cardiovascular centers in the medulla oblongata or the nervous fibers originating from this region

neuroglia

supportive neural cells

neuromuscular junction (NMJ)

synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal

neuron

excitable neural cell that transfer nerve impulses

neurotransmitter

signaling chemical released by nerve terminals that bind to and activate receptors on target cells

neutralization

inactivation of a virus by the binding of specific antibody

neutrophil

phagocytic white blood cell recruited from the bloodstream to the site of infection via the bloodstream

neutrophils

granulocytes that stain with a neutral dye and are the most numerous of the leukocytes; especially active against bacteria

neutron

heavy subatomic particle having no electrical charge and found in the atom’s nucleus

normal range

range of values around the set point that do not cause a reaction by the control center

nuchal ligament

expanded portion of the supraspinous ligament within the posterior neck; interconnects the spinous processes of the cervical vertebrae and attaches to the base of the skull

nuclear envelope

membrane that surrounds the nucleus; consisting of a double lipid-bilayer

nuclear pore

one of the small, protein-lined openings found scattered throughout the nuclear envelope

nucleolus

small region of the nucleus that functions in ribosome synthesis

nucleosome

unit of chromatin consisting of a DNA strand wrapped around histone proteins

nucleotide

class of organic compounds composed of one or more phosphate groups, a pentose sugar, and a base

nucleus

cell’s central organelle; contains the cell’s DNA

nucleus pulposus

gel-like central region of an intervertebral disc; provides for padding, weight-bearing, and movement between adjacent vertebrae

nutrient

chemical obtained from foods and beverages that is critical to human survival

nutrient foramen

small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment

oblique

at an angle

obstructive shock

type of shock that occurs when a significant portion of the vascular system is blocked

obturator foramen

large opening located in the anterior hip bone, between the pubis and ischium regions

obturator externus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

obturator internus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

occipital bone

unpaired bone that forms the posterior portions of the brain case and base of the skull

occipital condyle

paired, oval-shaped bony knobs located on the inferior skull, to either side of the foramen magnum

occipitalis

posterior part of the occipitofrontalis muscle

occipital sinus

enlarged vein that drains the occipital region near the falx cerebelli and flows into the left and right transverse sinuses, and also into the vertebral veins

occipitofrontalis

muscle that makes up the scalp with a frontal belly and an occipital belly

olecranon fossa

large depression located on the posterior side of the distal humerus; this space receives the olecranon process of the ulna when the elbow is fully extended

olecranon process

expanded posterior and superior portions of the proximal ulna; forms the bony tip of the elbow

oligodendrocyte

neuroglial cell that produces myelin in the brain

omohyoid

muscle that has superior and inferior bellies and depresses the hyoid bone

opponens digiti minimi

muscle that brings the little finger across the palm to meet the thumb

opponens pollicis

muscle that moves the thumb across the palm to meet another finger

opposition

thumb movement that brings the tip of the thumb in contact with the tip of a finger

opsonization

enhancement of phagocytosis by the binding of antibody or antimicrobial protein

ophthalmic artery

branch of the internal carotid artery; supplies blood to the eyes

optic canal

opening spanning between middle cranial fossa and posterior orbit

orbicularis oculi

circular muscle that closes the eye

orbicularis oris

circular muscle that moves the lips

orbit

bony socket that contains the eyeball and associated muscles

organelle

any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell

organic compound

substance that contains both carbon and hydrogen

origin

end of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position

oropharynx

portion of the pharynx flanked by the nasopharynx, oral cavity, and laryngopharynx that is a passageway for both air and food

orthopedist

doctor who specializes in diagnosing and treating musculoskeletal disorders and injuries

osmosis

diffusion of water molecules down their concentration gradient across a selectively permeable membrane

osseous tissue

bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton

ossification

(also, osteogenesis) bone formation

ossification center

cluster of osteoblasts found in the early stages of intramembranous ossification

osteoblast

cell responsible for forming new bone

osteoclast

cell responsible for resorbing bone

osteocyte

primary cell in mature bone; responsible for maintaining the matrix

osteogenic cell

undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts

osteoid

uncalcified bone matrix secreted by osteoblasts

osteon

(also, Haversian system) basic structural unit of compact bone; made of concentric layers of calcified matrix

ovarian artery

branch of the abdominal aorta; supplies blood to the ovary, uterine (Fallopian) tube, and uterus

ovarian vein

drains the ovary; the right ovarian vein leads to the inferior vena cava and the left ovarian vein leads to the left renal vein

oxyhemoglobin

(Hb–O₂) bound form of hemoglobin and oxygen

oxyhemoglobin

molecule of hemoglobin to which oxygen is bound

oxygen debt

amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction

oxygen–hemoglobin dissociation curve

graph that describes the relationship of partial pressure to the binding and disassociation of oxygen to and from heme

P wave

component of the electrocardiogram that represents the depolarization of the atria

pacemaker

cluster of specialized myocardial cells known as the SA node that initiates the sinus rhythm

Pacinian corpuscle

(also, lamellated corpuscle) receptor in the skin that responds to vibration

packed cell volume (PCV)

(also, hematocrit) volume percentage of erythrocytes present in a sample of centrifuged blood

palatine bone

paired bones that form the posterior quarter of the hard palate and a small area in floor of the orbit

palatine process

medial projection from the maxilla bone that forms the anterior three quarters of the hard palate

palatine tonsil

one of the paired structures composed of lymphoid tissue located anterior to the uvula at the roof of isthmus of the fauces

palatoglossus

muscle that originates on the soft palate to elevate the back of the tongue

palmar arches

superficial and deep arches formed from anastomoses of the radial and ulnar arteries; supply blood to the hand and digital arteries

palmar interossei

muscles that abduct and flex each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

palmaris longus

muscle that provides weak flexion of the hand at the wrist

palmar venous arches

drain the hand and digits, and feed into the radial and ulnar veins

papillary layer

superficial layer of the dermis, made of loose, areolar connective tissue

papillary muscle

extension of the myocardium in the ventricles to which the chordae tendineae attach

parallel

fascicles that extend in the same direction as the long axis of the muscle

paranasal sinus

one of the cavities within the skull that is connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consists of frontal, maxillary, sphenoidal, and ethmoidal sinuses

paranasal sinuses

cavities within the skull that are connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consist of frontal, maxillary, sphenoidal, and ethmoidal sinuses

parenchyma

functional cells of a gland or organ, in contrast with the supportive or connective tissue of a gland or organ

parietal bone

paired bones that form the upper, lateral sides of the skull

parietal branches

(also, somatic branches) group of arterial branches of the thoracic aorta; includes those that supply blood to the thoracic cavity, vertebral column, and the superior surface of the diaphragm

parietal pleura

outermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm

partial pressure

force exerted by each gas in a mixture of gases

passive immunity

transfer of immunity to a pathogen to an individual that lacks immunity to this pathogen usually by the injection of antibodies

passive transport

form of transport across the cell membrane that does not require input of cellular energy

patella

kneecap; the largest sesamoid bone of the body; articulates with the distal femur

patellar ligament

extension of the quadriceps tendon below the patella

patellar ligament

ligament spanning from the patella to the anterior tibia; serves as the final attachment for the quadriceps femoris muscle

patellar surface

smooth groove located on the anterior side of the distal femur, between the medial and lateral condyles; site of articulation for the patella

pattern recognition receptor (PRR)

leukocyte receptor that binds to specific cell wall components of different bacterial species

pectinate muscles

muscular ridges seen on the anterior surface of the right atrium

pectineal line

narrow ridge located on the superior surface of the superior pubic ramus

pectineus

muscle that abducts and flexes the femur at the hip

pectoral girdle

shoulder girdle; the set of bones, consisting of the scapula and clavicle, which attaches each upper limb to the axial skeleton

pectoral girdle

shoulder girdle, made up of the clavicle and scapula

pectoralis major

thick, fan-shaped axial muscle that covers much of the superior thorax

pectoralis minor

muscle that moves the scapula and assists in inhalation

pedicle

portion of the vertebral arch that extends from the vertebral body to the transverse process

pelvic brim

pelvic inlet; the dividing line between the greater and lesser pelvic regions; formed by the superior margin of the pubic symphysis, the pectineal lines of each pubis, the arcuate lines of each ilium, and the sacral promontory

pelvic diaphragm

muscular sheet that comprises the levator ani and the ischiococcygeus

pelvic girdle

hips, a foundation for the lower limb

pelvic girdle

hip girdle; consists of a single hip bone, which attaches a lower limb to the sacrum of the axial skeleton

pelvic inlet

pelvic brim

pelvic outlet

inferior opening of the lesser pelvis; formed by the inferior margin of the pubic symphysis, right and left ischiopubic rami and sacrotuberous ligaments, and the tip of the coccyx

pelvis

ring of bone consisting of the right and left hip bones, the sacrum, and the coccyx

peptide bond

covalent bond formed by dehydration synthesis between two amino acids

perforating canal

(also, Volkmann’s canal) channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum

perforin

molecule in NK cell and cytotoxic T cell granules that form pores in the membrane of a target cell

perfusion

distribution of blood into the capillaries so the tissues can be supplied

pericardial cavity

cavity surrounding the heart filled with a lubricating serous fluid that reduces friction as the heart contracts

pericardial sac

(also, pericardium) membrane that separates the heart from other mediastinal structures; consists of two distinct, fused sublayers: the fibrous pericardium and the parietal pericardium

pericardium

(also, pericardial sac) membrane that separates the heart from other mediastinal structures; consists of two distinct, fused sublayers: the fibrous pericardium and the parietal pericardium

pericardium

sac that encloses the heart

perichondrium

membrane that covers cartilage

perimysium

connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle

peritoneum

serous membrane that lines the abdominopelvic cavity and covers the organs found there

periodic table of the elements

arrangement of the elements in a table according to their atomic number; elements having similar properties because of their electron arrangements compose columns in the table, while elements having the same number of valence shells compose rows in the table

periosteum

fibrous membrane covering the outer surface of bone and continuous with ligaments

peripheral chemoreceptor

one of the specialized receptors located in the aortic arch and carotid arteries that sense changes in pH, carbon dioxide, or oxygen blood levels

peripheral protein

membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane

peripheral tolerance

mature B cell made tolerant by lack of T cell help

periodontal ligament

band of dense connective tissue that anchors the root of a tooth into the bony jaw socket

peroxisome

membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances

perpendicular plate of the ethmoid bone

downward, midline extension of the ethmoid bone that forms the superior portion of the nasal septum

petrous ridge

petrous portion of the temporal bone that forms a large, triangular ridge in the floor of the cranial cavity, separating the middle and posterior cranial fossae; houses the middle and inner ear structures

pH

negative logarithm of the hydrogen ion (H⁺) concentration of a solution

phagocytosis

endocytosis of large particles

phagocytosis

movement of material from the outside to the inside of the cells via vesicles made from invaginations of the plasma membrane

phalanx bone of the foot

(plural = phalanges) one of the 14 bones that form the toes; these include the proximal and distal phalanges of the big toe, and the proximal, middle, and distal phalanx bones of toes two through five

pharyngeal tonsil

structure composed of lymphoid tissue located in the nasopharynx

pharynx

region of the conducting zone that forms a tube of skeletal muscle lined with respiratory epithelium; located between the nasal conchae and the esophagus and trachea

phalanx bone of the hand

(plural = phalanges) one of the 14 bones that form the thumb and fingers; these include the proximal and distal phalanges of the thumb, and the proximal, middle, and distal phalanx bones of the fingers two through five

philtrum

concave surface of the face that connects the apex of the nose to the top lip

phospholipid

a lipid compound in which a phosphate group is combined with a diglyceride

phosphorylation

addition of one or more phosphate groups to an organic compound

physiology

science that studies the chemistry, biochemistry, and physics of the body’s functions

pinocytosis

endocytosis of fluid

pisiform

from the lateral side, the fourth of the four proximal carpal bones; articulates with the anterior surface of the triquetrum

plane

imaginary two-dimensional surface that passes through the body

plantar flexion

foot movement at the ankle in which the heel is lifted off of the ground

plasma

in blood, the liquid extracellular matrix composed mostly of water that circulates the formed elements and dissolved materials throughout the cardiovascular system

plasmin

blood protein active in fibrinolysis

platelet plug

accumulation and adhesion of platelets at the site of blood vessel injury

platelets

(also, thrombocytes) one of the formed elements of blood that consists of cell fragments broken off from megakaryocytes

pleura

serous membrane that lines the pleural cavity and covers the lungs

pluripotent

describes the condition of being able to differentiate into a large variety of cell types

pluripotent stem cell

stem cell that derives from totipotent stem cells and is capable of differentiating into many, but not all, cell types

pneumotaxic center

network of neurons within the pons that inhibit the activity of the neurons in the dorsal respiratory group; controls rate of breathing

polar molecule

molecule with regions that have opposite charges resulting from uneven numbers of electrons in the nuclei of the atoms participating in the covalent bond

pollex

(also, thumb) digit 1 of the hand

polyclonal response

response by multiple clones to a complex antigen with many determinants

polycythemia

elevated level of hemoglobin, whether adaptive or pathological

polymorphonuclear

having a lobed nucleus, as seen in some leukocytes

polypeptide

chain of amino acids linked by peptide bonds

polyribosome

simultaneous translation of a single mRNA transcript by multiple ribosomes

polysaccharide

compound consisting of more than two carbohydrate monomers bonded by dehydration synthesis via glycosidic bonds

polyspermy

penetration of an oocyte by more than one sperm

posterior

describes the back or direction toward the back of the body; also referred to as dorsal

posterior cavity

posterior body cavity that houses the brain and spinal cord; also referred to as dorsal cavity

posterior cardiac vein

vessel that parallels and drains the areas supplied by the marginal artery branch of the circumflex artery; drains into the great cardiac vein

posterior cranial fossa

deepest and most posterior cranial fossa; extends from the petrous ridge to the occipital bone

posterior interventricular artery

(also, posterior descending artery) branch of the right coronary artery that runs along the posterior portion of the interventricular sulcus toward the apex of the heart and gives rise to branches that supply the interventricular septum and portions of both ventricles

posterior interventricular sulcus

sulcus located between the left and right ventricles on the anterior surface of the heart

positive chemotaxis

process in which a cell is attracted to move in the direction of chemical stimuli

positive inotropic factors

factors that positively impact or increase heart contractility

positive selection

selection of thymocytes within the thymus that interact with self, but not non-self, MHC molecules

posterior scalene

smallest scalene muscle, located posterior to the middle scalene

potential energy

stored energy matter possesses because of the positioning or structure of its components

pennate

fascicles that are arranged differently based on their angles to the tendon

pericardial artery

branch of the thoracic aorta; supplies blood to the pericardium

perimysium

connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle

perineum

diamond-shaped region between the pubic symphysis, coccyx, and ischial tuberosities

petrosal sinus

enlarged vein that receives blood from the cavernous sinus and flows into the internal jugular vein

phrenic vein

drains the diaphragm; the right phrenic vein flows into the inferior vena cava and the left phrenic vein leads to the left renal vein

piriformis

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

plantar aponeurosis

muscle that supports the longitudinal arch of the foot

plantar arch

formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits

plantar group

four-layered group of intrinsic foot muscles

plantaris

muscle that runs obliquely between the gastrocnemius and the soleus

plantar veins

drain the foot and lead to the plantar venous arch

plantar venous arch

formed from the plantar veins; leads to the anterior and posterior tibial veins through anastomoses

plasma cell

differentiated B cell that is actively secreting antibody

pleural cavity

space between the visceral and parietal pleurae

pleural fluid

substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing

popliteal artery

continuation of the femoral artery posterior to the knee; branches into the anterior and posterior tibial arteries

popliteal fossa

diamond-shaped space at the back of the knee

popliteal vein

continuation of the femoral vein behind the knee; drains the region behind the knee and forms from the fusion of the fibular and anterior and posterior tibial veins

popliteus

muscle that flexes the leg at the knee and creates the floor of the popliteal fossa

positive feedback

mechanism that intensifies a change in the body’s physiological condition in response to a stimulus

posterior arch

posterior portion of the ring-like C1 (atlas) vertebra

posterior cerebral artery

branch of the basilar artery that forms a portion of the posterior segment of the arterial circle; supplies blood to the posterior portion of the cerebrum and brain stem

posterior communicating artery

branch of the posterior cerebral artery that forms part of the posterior portion of the arterial circle; supplies blood to the brain

posterior compartment of the leg

region that includes the superficial gastrocnemius, soleus, and plantaris, and the deep popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior

posterior compartment of the thigh

region that includes muscles that flex the leg and extend the thigh

posterior cruciate ligament

intracapsular ligament of the knee; extends from the posterior, superior surface of the tibia to the inner aspect of the medial condyle of the femur; prevents anterior displacement of the femur when the knee is flexed and weight bearing

posterior longitudinal ligament

ligament that runs the length of the vertebral column, uniting the posterior sides of the vertebral bodies

posterior (dorsal) sacral foramen

one of the series of paired openings located on the posterior (dorsal) side of the sacrum

posterior talofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between the talus bone and lateral malleolus of the fibula; supports the talus at the talocrural joint and resists excess inversion of the foot

posterior tibial artery

branch from the popliteal artery that gives rise to the fibular or peroneal artery; supplies blood to the posterior tibial region

posterior tibial vein

forms from the dorsal venous arch; drains the area near the posterior surface of the tibia and leads to the popliteal vein

posterior inferior iliac spine

small, bony projection located at the inferior margin of the auricular surface on the posterior ilium

posterior sacroiliac ligament

strong ligament spanning the sacrum and ilium of the hip bone that supports the posterior side of the sacroiliac joint

posterior superior iliac spine

rounded, posterior end of the iliac crest

power stroke

action of myosin pulling actin inward (toward the M line)

precapillary sphincters

circular rings of smooth muscle that surround the entrance to a capillary and regulate blood flow into that capillary

preload

(also, end diastolic volume) amount of blood in the ventricles at the end of atrial systole just prior to ventricular contraction

prepotential depolarization

(also, spontaneous depolarization) mechanism that accounts for the autorhythmic property of cardiac muscle; the membrane potential increases as sodium ions diffuse through the always-open sodium ion channels and causes the electrical potential to rise

pressure

force exerted by a substance in contact with another substance

primary adaptive response

immune system’s response to the first exposure to a pathogen

primary curve

anteriorly concave curvatures of the thoracic and sacrococcygeal regions that are retained from the original fetal curvature of the vertebral column

primary lymphoid organ

site where lymphocytes mature and proliferate; red bone marrow and thymus gland

primary ossification center

region, deep in the periosteal collar, where bone development starts during endochondral ossification

prime mover

(also, agonist) principle muscle involved in an action

product

one or more substances produced by a chemical reaction

projection

bone markings where part of the surface sticks out above the rest of the surface, where tendons and ligaments attach

proliferative zone

region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate

promoter

region of DNA that signals transcription to begin at that site within the gene

pronated position

forearm position in which the palm faces backward

pronation

forearm motion that moves the palm of the hand from the palm forward to the palm backward position

pronator quadratus

pronator that originates on the ulna and inserts on the radius

pronator teres

pronator that originates on the humerus and inserts on the radius

prone

face down

prophase

first stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes

prostaglandin

lipid compound derived from fatty acid chains and important in regulating several body processes

protein

class of organic compounds that are composed of many amino acids linked together by peptide bonds

proteome

full complement of proteins produced by a cell (determined by the cell’s specific gene expression)

proton

heavy subatomic particle having a positive charge and found in the atom’s nucleus

protraction

anterior motion of the scapula or mandible

proximal

describes a position nearer to the point of attachment or the trunk of the body

proximal radioulnar joint

articulation formed by the radial notch of the ulna and the head of the radius

proximal tibiofibular joint

articulation between the head of the fibula and the inferior aspect of the lateral condyle of the tibia

psychoneuroimmunology

study of the connections between the immune, nervous, and endocrine systems

psoas major

muscle that, along with the iliacus, makes up the iliopsoas

pterion

H-shaped suture junction region that unites the frontal, parietal, temporal, and sphenoid bones on the lateral side of the skull

pubic arch

bony structure formed by the pubic symphysis, and the bodies and inferior pubic rami of the right and left pubic bones

pubic body

enlarged, medial portion of the pubis region of the hip bone

pubic symphysis

joint formed by the articulation between the pubic bodies of the right and left hip bones

pubic tubercle

small bump located on the superior aspect of the pubic body

pubis

anterior portion of the hip bone

pubococcygeus

muscle that makes up the levator ani along with the iliococcygeus

pubofemoral ligament

intrinsic ligament spanning from the pubis of the hip bone to the femur, on the anterior-inferior aspect of the hip joint

pulmonary artery

one of two branches, left and right, that divides off from the pulmonary trunk and leads to smaller arterioles and eventually to the pulmonary capillaries

pulmonary arteries

left and right branches of the pulmonary trunk that carry deoxygenated blood from the heart to each of the lungs

pulmonary artery

artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli

pulmonary capillaries

capillaries surrounding the alveoli of the lungs where gas exchange occurs: carbon dioxide exits the blood and oxygen enters

pulmonary circuit

blood flow to and from the lungs

pulmonary circuit

system of blood vessels that provide gas exchange via a network of arteries, veins, and capillaries that run from the heart, through the body, and back to the lungs

pulmonary plexus

network of autonomic nervous system fibers found near the hilum of the lung

pulmonary surfactant

substance composed of phospholipids and proteins that reduces the surface tension of the alveoli; made by type II alveolar cells

pulmonary trunk

large arterial vessel that carries blood ejected from the right ventricle; divides into the left and right pulmonary arteries

pulmonary trunk

single large vessel exiting the right ventricle that divides to form the right and left pulmonary arteries

pulmonary veins

two sets of paired vessels, one pair on each side, that are formed from the small venules leading away from the pulmonary capillaries that flow into the left atrium

pulmonary valve

(also, pulmonary semilunar valve, the pulmonic valve, or the right semilunar valve) valve at the base of the pulmonary trunk that prevents backflow of blood into the right ventricle; consists of three flaps

pulmonary veins

veins that carry highly oxygenated blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and to the many branches of the systemic circuit

pulmonary ventilation

exchange of gases between the lungs and the atmosphere; breathing

pulse

alternating expansion and recoil of an artery as blood moves through the vessel; an indicator of heart rate

pulse pressure

difference between the systolic and diastolic pressures

purine

nitrogen-containing base with a double ring structure; adenine and guanine

purkinje fibers

specialized myocardial conduction fibers that arise from the bundle branches and spread the impulse to the myocardial contraction fibers of the ventricles

pyrimidine

nitrogen-containing base with a single ring structure; cytosine, thiamine, and uracil

pyruvic acid

product of glycolysis that can be used in aerobic respiration or converted to lactic acid

QRS complex

component of the electrocardiogram that represents the depolarization of the ventricles and includes, as a component, the repolarization of the atria

quadratus femoris

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

quadriceps femoris group

four muscles, that extend and stabilize the knee

quadratus lumborum

posterior part of the abdominal wall that helps with posture and stabilization of the body

quadriceps tendon

(also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella

quiet breathing

(also, eupnea) mode of breathing that occurs at rest and does not require the cognitive thought of the individual

radial artery

formed at the bifurcation of the brachial artery; parallels the radius; gives off smaller branches until it reaches the carpal region where it fuses with the ulnar artery to form the superficial and deep palmar arches; supplies blood to the lower arm and carpal region

radial collateral ligament

intrinsic ligament on the lateral side of the elbow joint; runs from the lateral epicondyle of humerus to merge with the annular ligament

radial fossa

small depression located on the anterior humerus above the capitulum; this space receives the head of the radius when the elbow is maximally flexed

radial notch of the ulna

small, smooth area on the lateral side of the proximal ulna; articulates with the head of the radius as part of the proximal radioulnar joint

radial tuberosity

oval-shaped, roughened protuberance located on the medial side of the proximal radius

radial vein

parallels the radius and radial artery; arises from the palmar venous arches and leads to the brachial vein

radiation

transfer of heat via infrared waves

radioactive isotope

unstable, heavy isotope that gives off subatomic particles, or electromagnetic energy, as it decays; also called radioisotopes

radiocarpal joint

wrist joint, located between the forearm and hand regions of the upper limb; articulation formed proximally by the distal end of the radius and the fibrocartilaginous pad that unites the distal radius and ulna bone, and distally by the scaphoid, lunate, and triquetrum carpal bones

radius

bone located on the lateral side of the forearm

ramus of the mandible

vertical portion of the mandible

reabsorption

in the cardiovascular system, the movement of material from the interstitial fluid into the capillaries

reactant

one or more substances that enter into the reaction

reactive oxygen species (ROS)

a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage

receptor

protein molecule that contains a binding site for another specific molecule (called a ligand)

receptor-mediated endocytosis

endocytosis of ligands attached to membrane-bound receptors

recruitment

increase in the number of motor units involved in contraction

rectus

straight

rectus abdominis

long, linear muscle that extends along the middle of the trunk

rectus femoris

quadricep muscle on the anterior aspect of the thigh

rectus sheaths

tissue that makes up the linea alba

red blood cells (RBCs)

(also, erythrocytes) one of the formed elements of blood that transports oxygen

red marrow

connective tissue in the interior cavity of a bone where hematopoiesis takes place

regional anatomy

study of the structures that contribute to specific body regions

regulatory T cells (Treg)

(also, suppressor T cells) class of CD4 T cells that regulates other T cell responses

relaxation phase

period after twitch contraction when tension decreases

remodeling

process by which osteoclasts resorb old or damaged bone at the same time as and on the same surface where osteoblasts form new bone to replace that which is resorbed

renal artery

branch of the abdominal aorta; supplies each kidney

renal vein

largest vein entering the inferior vena cava; drains the kidneys and leads to the inferior vena cava

reposition

movement of the thumb from opposition back to the anatomical position (next to index finger)

reproduction
is the formation of a new organism from parent organisms. In humans, reproduction is carried out by the male and female reproductive systems. Because death will come to all complex organisms, without reproduction, the line of organisms would end.

reserve zone

region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis

residual volume (RV)

amount of air that remains in the lungs after maximum exhalation

resistance

any condition or parameter that slows or counteracts the flow of blood

respiratory bronchiole

specific type of bronchiole that leads to alveolar sacs

respiratory cycle

one sequence of inspiration and expiration

respiratory epithelium

ciliated lining of much of the conducting zone that is specialized to remove debris and pathogens, and produce mucus

respiratory membrane

alveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases

respiratory pump

increase in the volume of the thorax during inhalation that decreases air pressure, enabling venous blood to flow into the thoracic region, then exhalation increases pressure, moving blood into the atria

respiratory rate

total number of breaths taken each minute

respiratory volume

varying amounts of air within the lung at a given time

respiratory zone

includes structures of the respiratory system that are directly involved in gas exchange

reticular fiber

fine fibrous protein, made of collagen subunits, which cross-link to form supporting “nets” within connective tissue

reticular layer

deeper layer of the dermis; it has a reticulated appearance due to the presence of abundant collagen and elastin fibers

reticular tissue

type of loose connective tissue that provides a supportive framework to soft organs, such as lymphatic tissue, spleen, and the liver

reticulocyte

immature erythrocyte that may still contain fragments of organelles

retraction

posterior motion of the scapula or mandible

Rh blood group

blood-type classification based on the presence or absence of the antigen Rh on the erythrocyte membrane surface.

rhomboid major

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

rhomboid minor

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

ribonucleic acid (RNA)

ribose-containing nucleotide that helps manifest the genetic code as protein

ribosome

cellular organelle that functions in protein synthesis

ribosomal RNA (rRNA)

RNA that makes up the subunits of a ribosome

ribs

thin, curved bones of the chest wall

rickets

disease in children caused by vitamin D deficiency, which leads to the weakening of bones

right atrioventricular valve

(also, tricuspid valve) valve located between the right atrium and ventricle; consists of three flaps of tissue

right gastric artery

branch of the common hepatic artery; supplies blood to the stomach

right lymphatic duct

drains lymph fluid from the upper right side of body into the right subclavian vein

RNA polymerase

enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis

root

region of the external nose between the eyebrows

rotation

movement of a bone around a central axis (atlantoaxial joint) or around its long axis (proximal radioulnar joint; shoulder or hip joint); twisting of the vertebral column resulting from the summation of small motions between adjacent vertebrae

rotator cuff

(also, musculotendinous cuff) the circle of tendons around the shoulder joint

rotator cuff

strong connective tissue structure formed by the fusion of four rotator cuff muscle tendons to the articular capsule of the shoulder joint; surrounds and supports superior, anterior, lateral, and posterior sides of the humeral head

sacral canal

bony tunnel that runs through the sacrum

sacral foramina

series of paired openings for nerve exit located on both the anterior (ventral) and posterior (dorsal) aspects of the sacrum

sacral hiatus

inferior opening and termination of the sacral canal

sacral promontory

anterior lip of the base (superior end) of the sacrum

sacrococcygeal curve

anteriorly concave curvature formed by the sacrum and coccyx; a primary curve of the vertebral column

sacroiliac joint

joint formed by the articulation between the auricular surfaces of the sacrum and ilium

sacrospinous ligament

ligament that spans the sacrum to the ischial spine of the hip bone

sacrotuberous ligament

ligament that spans the sacrum to the ischial tuberosity of the hip bone

sacrum

single bone located near the inferior end of the adult vertebral column that is formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis

sagittal plane

two-dimensional, vertical plane that divides the body or organ into right and left sides

sagittal suture

joint that unites the right and left parietal bones at the midline along the top of the skull

sarcomere

longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction

sarcomere

longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction

sarcolemma

plasma membrane of a skeletal muscle fiber

sarcolemma

plasma membrane of a skeletal muscle fiber

sarcopenia

age-related muscle atrophy

sarcoplasm

cytoplasm of a muscle cell

sarcoplasm

cytoplasm of a muscle cell

sarcoplasmic reticulum (SR)

specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca⁺⁺

sarcoplasmic reticulum (SR)

specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca⁺⁺

sartorius

band-like muscle that flexes, abducts, and laterally rotates the leg at the hip

scalene muscles

flex, laterally flex, and rotate the head; contribute to deep inhalation

scaphoid

from the lateral side, the first of the four proximal carpal bones; articulates with the radius proximally, the trapezoid, trapezium, and capitate distally, and the lunate medially

scapula

shoulder blade bone located on the posterior side of the shoulder

Schwann cell

neuroglial cell that produces myelin in the peripheral nervous system

scoliosis

abnormal lateral curvature of the vertebral column

sebaceous gland

type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum

sebum

oily substance that is composed of a mixture of lipids that lubricates the skin and hair

secondary adaptive response

immune response observed upon re-exposure to a pathogen, which is stronger and faster than a primary response

secondary curve

posteriorly concave curvatures of the cervical and lumbar regions of the vertebral column that develop after the time of birth

secondary lymphoid organs

sites where lymphocytes mount adaptive immune responses; examples include lymph nodes and spleen

secondary ossification center

region of bone development in the epiphyses

section

in anatomy, a single flat surface of a three-dimensional structure that has been cut through

segmental muscle group

interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra

selective permeability

feature of any barrier that allows certain substances to cross but excludes others

sella turcica

elevated area of sphenoid bone located at midline of the middle cranial fossa

semilunar valves

valves located at the base of the pulmonary trunk and at the base of the aorta

semimembranosus

hamstring muscle

semispinalis capitis

transversospinales muscle associated with the head region

semispinalis cervicis

transversospinales muscle associated with the cervical region

semispinalis thoracis

transversospinales muscle associated with the thoracic region

semitendinosus

hamstring muscle

sensitization

first exposure to an antigen

sensor

(also, receptor) reports a monitored physiological value to the control center

sepsis

(also, septicemia) organismal-level inflammatory response to a massive infection

septal cartilage

flat cartilage structure that forms the anterior portion of the nasal septum

septum

(plural = septa) walls or partitions that divide the heart into chambers

septum primum

flap of tissue in the fetus that covers the foramen ovale within a few seconds after birth

seroconversion

clearance of pathogen in the serum and the simultaneous rise of serum antibody

serosa

membrane that covers organs and reduces friction; also referred to as serous membrane

serous membrane

type of tissue membrane that lines body cavities and lubricates them with serous fluid

serous membrane

membrane that covers organs and reduces friction; also referred to as serosa

serratus anterior

large and flat muscle that originates on the ribs and inserts onto the scapula

serum

blood plasma that does not contain clotting factors

sesamoid bone

small, round bone embedded in a tendon; protects the tendon from compressive forces

set point

ideal value for a physiological parameter; the level or small range within which a physiological parameter such as blood pressure is stable and optimally healthful, that is, within its parameters of homeostasis

severe combined immunodeficiency disease (SCID)

genetic mutation that affects both T cell and B cell arms of the immune response

shaft of the femur

cylindrically shaped region that forms the central portion of the femur

shaft of the fibula

elongated, slender portion located between the expanded ends of the fibula

shaft of the humerus

narrow, elongated, central region of the humerus

shaft of the radius

narrow, elongated, central region of the radius

shaft of the tibia

triangular-shaped, central portion of the tibia

shaft of the ulna

narrow, elongated, central region of the ulna

short bone

cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion

sickle cell disease

(also, sickle cell anemia) inherited blood disorder in which hemoglobin molecules are malformed, leading to the breakdown of RBCs that take on a characteristic sickle shape

sigmoid sinuses

enlarged veins that receive blood from the transverse sinuses; flow through the jugular foramen and into the internal jugular vein

sinoatrial (SA) node

known as the pacemaker, a specialized clump of myocardial conducting cells located in the superior portion of the right atrium that has the highest inherent rate of depolarization that then spreads throughout the heart

sinus rhythm

normal contractile pattern of the heart

sinusoid capillary

rarest type of capillary, which has extremely large intercellular gaps in the basement membrane in addition to clefts and fenestrations; found in areas such as the bone marrow and liver where passage of large molecules occurs

sister chromatid

one of a pair of identical chromosomes, formed during DNA replication

skeletal muscle

usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated

skeletal muscle

striated, multinucleated muscle that requires signaling from the nervous system to trigger contraction; most skeletal muscles are referred to as voluntary muscles that move bones and produce movement

skeletal muscle pump

effect on increasing blood pressure within veins by compression of the vessel caused by the contraction of nearby skeletal muscle

skeletal system

organ system composed of bones and cartilage that provides for movement, support, and protection

skeleton

bones of the body

skull

bony structure that forms the head, face, and jaws, and protects the brain; consists of 22 bones

small cardiac vein

parallels the right coronary artery and drains blood from the posterior surfaces of the right atrium and ventricle; drains into the great cardiac vein

small saphenous vein

located on the lateral surface of the leg; drains blood from the superficial regions of the lower leg and foot, and leads to the popliteal vein

smooth muscle

under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, and do not appear striated; each cell is a fiber

smooth muscle

nonstriated, mononucleated muscle in the skin that is associated with hair follicles; assists in moving materials in the walls of internal organs, blood vessels, and internal passageways

sodium-potassium pump

(also, Na⁺/K⁺ ATP-ase) membrane-embedded protein pump that uses ATP to move Na⁺ out of a cell and K⁺ into the cell

soleal line

small, diagonally running ridge located on the posterior side of the proximal tibia

soleus

wide, flat muscle deep to the gastrocnemius

solution

homogeneous liquid mixture in which a solute is dissolved into molecules within a solvent

somatic cell

all cells of the body excluding gamete cells

S phase

stage of the cell cycle during which DNA replication occurs

sphenoid bone

unpaired bone that forms the central base of skull

sphenoid sinus

air-filled space located within the sphenoid bone; most posterior of the paranasal sinuses

sphincter urethrovaginalis

deep perineal muscle in women

sphygmomanometer

blood pressure cuff attached to a device that measures blood pressure

spinal cavity

division of the dorsal cavity that houses the spinal cord; also referred to as vertebral cavity

spinalis capitis

muscle of the spinalis group associated with the head region

spinalis cervicis

muscle of the spinalis group associated with the cervical region

spinalis group

medially placed muscles of the erector spinae

spinalis thoracis

muscle of the spinalis group associated with the thoracic region

spine of the scapula

prominent ridge passing mediolaterally across the upper portion of the posterior scapular surface

spinous process

unpaired bony process that extends posteriorly from the vertebral arch of a vertebra

spleen

secondary lymphoid organ that filters pathogens from the blood (white pulp) and removes degenerating or damaged blood cells (red pulp)

splenius

posterior neck muscles; includes the splenius capitis and splenius cervicis

splenius capitis

neck muscle that inserts into the head region

splenius cervicis

neck muscle that inserts into the cervical region

splenic artery

branch of the celiac trunk; supplies blood to the spleen

spliceosome

complex of enzymes that serves to splice out the introns of a pre-mRNA transcript

splicing

the process of modifying a pre-mRNA transcript by removing certain, typically non-coding, regions

spongy bone

(also, cancellous bone) trabeculated osseous tissue that supports shifts in weight distribution

spontaneous depolarization

(also, prepotential depolarization) the mechanism that accounts for the autorhythmic property of cardiac muscle; the membrane potential increases as sodium ions diffuse through the always-open sodium ion channels and causes the electrical potential to rise

squamous suture

joint that unites the parietal bone to the squamous portion of the temporal bone on the lateral side of the skull

stem cell

cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized

sternal angle

junction line between manubrium and body of the sternum and the site for attachment of the second rib to the sternum

sternal end of the clavicle

medial end of the clavicle that articulates with the manubrium of the sternum

sternoclavicular joint

articulation between the manubrium of the sternum and the sternal end of the clavicle; forms the only bony attachment between the pectoral girdle of the upper limb and the axial skeleton

sternocleidomastoid

major muscle that laterally flexes and rotates the head

sternohyoid

muscle that depresses the hyoid bone

sternothyroid

muscle that depresses the larynx’s thyroid cartilage

sternum

flattened bone located at the center of the anterior chest

steroid

(also, sterol) lipid compound composed of four hydrocarbon rings bonded to a variety of other atoms and molecules

straight sinus

enlarged vein that drains blood from the brain; receives most of the blood from the great cerebral vein and flows into the left or right transverse sinus

stratum basale

deepest layer of the epidermis, made of epidermal stem cells

stratum corneum

most superficial layer of the epidermis

stratum granulosum

layer of the epidermis superficial to the stratum spinosum

stratum lucidum

layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits

stratum spinosum

layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes

striation

alignment of parallel actin and myosin filaments which form a banded pattern

stroke volume (SV)

amount of blood pumped by each ventricle per contraction; also, the difference between EDV and ESV

styloglossus

muscle that originates on the styloid bone, and allows upward and backward motion of the tongue

stylohyoid

muscle that elevates the hyoid bone posteriorly

styloid process

downward projecting, elongated bony process located on the inferior aspect of the skull

styloid process of the radius

pointed projection located on the lateral end of the distal radius

styloid process of the ulna

short, bony projection located on the medial end of the distal ulna

stylomastoid foramen

opening located on inferior skull, between the styloid process and mastoid process

subacromial bursa

bursa that protects the supraspinatus muscle tendon and superior end of the humerus from rubbing against the acromion of the scapula

subclavian artery

right subclavian arises from the brachiocephalic artery, whereas the left subclavian artery arises from the aortic arch; gives rise to the internal thoracic, vertebral, and thyrocervical arteries; supplies blood to the arms, chest, shoulders, back, and central nervous system

subclavian vein

located deep in the thoracic cavity; becomes the axillary vein as it enters the axillary region; drains the axillary and smaller local veins near the scapular region; leads to the brachiocephalic vein

subclavius

muscle that stabilizes the clavicle during movement

subpubic angle

inverted V-shape formed by the convergence of the right and left ischiopubic rami; this angle is greater than 80 degrees in females and less than 70 degrees in males

subscapular bursa

bursa that prevents rubbing of the subscapularis muscle tendon against the scapula

subscapular fossa

broad depression located on the anterior (deep) surface of the scapula

subscapularis

muscle that originates on the anterior scapula and medially rotates the arm

subscapular vein

drains blood from the subscapular region and leads to the axillary vein

substrate

reactant in an enzymatic reaction

subtalar joint

articulation between the talus and calcaneus bones of the foot; allows motions that contribute to inversion/eversion of the foot

sudoriferous gland

sweat gland

sulcus

(plural = sulci) fat-filled groove visible on the surface of the heart; coronary vessels are also located in these areas

superficial

describes a position nearer to the surface of the body

superior

describes a position above or higher than another part of the body proper; also referred to as cranial

superficial anterior compartment of the forearm

flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and their associated blood vessels and nerves

superficial posterior compartment of the forearm

extensor radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and their associated blood vessels and nerves

superior angle of the scapula

corner of the scapula between the superior and medial borders of the scapula

superior articular process

bony process that extends upward from the vertebral arch of a vertebra that articulates with the inferior articular process of the next higher vertebra

superior articular process of the sacrum

paired processes that extend upward from the sacrum to articulate (join) with the inferior articular processes from the L5 vertebra

superior border of the scapula

superior margin of the scapula

superior extensor retinaculum

transverse ligament of the ankle

superior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

superior mesenteric artery

branch of the abdominal aorta; supplies blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine

superior nasal concha

smallest and most superiorly located of the nasal conchae; formed by the ethmoid bone

superior nuchal line

paired bony lines on the posterior skull that extend laterally from the external occipital protuberance

superior orbital fissure

irregularly shaped opening between the middle cranial fossa and the posterior orbit

superior phrenic artery

branch of the thoracic aorta; supplies blood to the superior surface of the diaphragm

superior pubic ramus

narrow segment of bone that passes laterally from the pubic body to join the ilium

superior rotation

movement of the scapula during upper limb abduction in which the glenoid cavity of the scapula moves in an upward direction as the medial end of the scapular spine moves in a downward direction

superior sagittal sinus

enlarged vein located midsagittally between the meningeal and periosteal layers of the dura mater within the falx cerebri; receives most of the blood drained from the superior surface of the cerebrum and leads to the inferior jugular vein and the vertebral vein

superior vena cava

large systemic vein; drains blood from most areas superior to the diaphragm; empties into the right atrium

superior vena cava

large systemic vein that returns blood to the heart from the superior portion of the body

supinated position

forearm position in which the palm faces anteriorly (anatomical position)

supination

forearm motion that moves the palm of the hand from the palm backward to the palm forward position

supinator

muscle that moves the palm and forearm anteriorly

supine

face up

supraglenoid tubercle

small bump located at the superior margin of the glenoid cavity

suprahyoid muscles

neck muscles that are superior to the hyoid bone

suprascapular notch

small notch located along the superior border of the scapula, medial to the coracoid process

supraspinous fossa

narrow depression located on the posterior scapula, superior to the spine

supraspinous ligament

ligament that interconnects the spinous processes of the thoracic and lumbar vertebrae

supportive connective tissue

type of connective tissue that provides strength to the body and protects soft tissue

supraorbital foramen

opening located on anterior skull, at the superior margin of the orbit

supraorbital margin

superior margin of the orbit

supraspinatus

muscle that abducts the arm

surgical neck

region of the humerus where the expanded, proximal end joins with the narrower shaft

suspension

liquid mixture in which particles distributed in the liquid settle out over time

sustentaculum tali

bony ledge extending from the medial side of the calcaneus bone

suture

fibrous joint that connects the bones of the skull (except the mandible); an immobile joint (synarthrosis)

suture

junction line at which adjacent bones of the skull are united by fibrous connective tissue

synaptic cleft

space between a nerve (axon) terminal and a motor end-plate

synaptic cleft

space between a nerve (axon) terminal and a motor end-plate

synarthrosis

immobile or nearly immobile joint

syndesmosis

type of fibrous joint in which two separated, parallel bones are connected by an interosseous membrane

synergist

muscle whose contraction helps a prime mover in an action

synostosis

site at which adjacent bones or bony components have fused together

synovial joint

joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule

synovial membrane

connective tissue membrane that lines the cavities of freely movable joints, producing synovial fluid for lubrication

synthesis reaction

type of anabolic reaction in which two or more atoms or molecules bond, resulting in the formation of a larger molecule

systemic anatomy

study of the structures that contribute to specific body systems

systemic circuit

blood flow to and from virtually all of the tissues of the body

systolic pressure

larger number recorded when measuring arterial blood pressure; represents the maximum value following ventricular contraction

systole
period of time when the heart muscle is contracting

talus

tarsal bone that articulates superiorly with the tibia and fibula at the ankle joint; also articulates inferiorly with the calcaneus bone and anteriorly with the navicular bone

target heart rate

range in which both the heart and lungs receive the maximum benefit from an aerobic workout

tarsal bone

one of the seven bones that make up the posterior foot; includes the calcaneus, talus, navicular, cuboid, medial cuneiform, intermediate cuneiform, and lateral cuneiform bones

talocrural joint

ankle joint; articulation between the talus bone of the foot and medial malleolus of the tibia, distal tibia, and lateral malleolus of the fibula; a uniaxial hinge joint that allows only for dorsiflexion and plantar flexion of the foot

T cell

lymphocyte that acts by secreting molecules that regulate the immune system or by causing the destruction of foreign cells, viruses, and cancer cells

T cell-dependent antigen

antigen that binds to B cells, which requires signals from T cells to make antibody

T cell-independent antigen

binds to B cells, which do not require signals from T cells to make antibody

telophase

final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei

temporal bone

paired bones that form the lateral, inferior portions of the skull, with squamous, mastoid, and petrous portions

temporal fossa

shallow space on the lateral side of the skull, above the level of the zygomatic arch

temporalis

muscle that retracts the mandible

temporal process of the zygomatic bone

short extension from the zygomatic bone that forms the anterior portion of the zygomatic arch

temporal vein

drains blood from the temporal region and leads to the external jugular vein

temporomandibular joint (TMJ)

articulation between the condyle of the mandible and the mandibular fossa and articular tubercle of the temporal bone of the skull; allows for depression/elevation (opening/closing of mouth), protraction/retraction, and side-to-side motions of the mandible

tendinous intersections

three transverse bands of collagen fibers that divide the rectus abdominis into segments

tensor fascia lata

muscle that flexes and abducts the thigh

teres major

muscle that extends the arm and assists in adduction and medial rotation of it

teres minor

muscle that laterally rotates and extends the arm

testicular artery

branch of the abdominal aorta; will ultimately travel outside the body cavity to the testes and form one component of the spermatic cord

testicular vein

drains the testes and forms part of the spermatic cord; the right testicular vein empties directly into the inferior vena cava and the left testicular vein empties into the left renal vein

tetanus

a continuous fused contraction

thoroughfare channel

continuation of the metarteriole that enables blood to bypass a capillary bed and flow directly into a venule, creating a vascular shunt

thrombin

enzyme essential for the final steps in formation of a fibrin clot

thrombocytes

platelets, one of the formed elements of blood that consists of cell fragments broken off from megakaryocytes

thrombocytopenia

condition in which there are too few platelets, resulting in abnormal bleeding (hemophilia)

thrombocytosis

condition in which there are too many platelets, resulting in abnormal clotting (thrombosis)

thrombopoietin

hormone secreted by the liver and kidneys that prompts the development of megakaryocytes into thrombocytes (platelets)

thrombosis

excessive clot formation

thrombus

aggregation of fibrin, platelets, and erythrocytes in an intact artery or vein

thymocyte

immature T cell found in the thymus

thymus

primary lymphoid organ; where T lymphocytes proliferate and mature

thyrocervical artery

arises from the subclavian artery; supplies blood to the thyroid, the cervical region, the upper back, and shoulder

thyrohyoid

muscle that depresses the hyoid bone and elevates the larynx’s thyroid cartilage

thyroid cartilage

largest piece of cartilage that makes up the larynx and consists of two lamina

tibia

shin bone; the large, weight-bearing bone located on the medial side of the leg

tibialis anterior

muscle located on the lateral surface of the tibia

tibial collateral ligament

extrinsic ligament of knee joint that spans from the medial epicondyle of the femur to the medial tibia; resists hyperextension and rotation of extended knee

tibialis posterior

muscle that plantar flexes and inverts the foot

tibial tuberosity

elevated area on the anterior surface of the proximal tibia

tidal volume (TV)

amount of air that normally enters the lungs during quiet breathing

tissue

group of cells that are similar in form and perform related functions

tissue factor

protein thromboplastin, which initiates the extrinsic pathway when released in response to tissue damage

tissue membrane

thin layer or sheet of cells that covers the outside of the body, organs, and internal cavities

tissue typing

typing of MHC molecules between a recipient and donor for use in a potential transplantation procedure

T lymphocytes

(also, T cells) lymphocytes that provide cellular-level immunity by physically attacking foreign or diseased cells

tonsils

lymphoid nodules associated with the nasopharynx

total dead space

sum of the anatomical dead space and alveolar dead space

total lung capacity (TLC)

total amount of air that can be held in the lungs; sum of TV, ERV, IRV, and RV

total pressure

sum of all the partial pressures of a gaseous mixture

totipotent

embryonic cells that have the ability to differentiate into any type of cell and organ in the body

totipotent stem cell

embryonic stem cell that is capable of differentiating into any and all cells of the body; enabling the full development of an organism

trabeculae

(singular = trabecula) spikes or sections of the lattice-like matrix in spongy bone

trabeculae carneae

ridges of muscle covered by endocardium located in the ventricles

trachea

tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung

trachealis muscle

smooth muscle located in the fibroelastic membrane of the trachea

transcription

process of producing an mRNA molecule that is complementary to a particular gene of DNA

transcription factor

one of the proteins that regulate the transcription of genes

transferrin

plasma protein that binds reversibly to iron and distributes it throughout the body

transfer RNA (tRNA)

molecules of RNA that serve to bring amino acids to a growing polypeptide strand and properly place them into the sequence

transient ischemic attack (TIA)

temporary loss of neurological function caused by a brief interruption in blood flow; also known as a mini-stroke

transverse sinuses

pair of enlarged veins near the lambdoid suture that drain the occipital, sagittal, and straight sinuses, and leads to the sigmoid sinuses

transpulmonary pressure

pressure difference between the intrapleural and intra-alveolar pressures

transverse foramen

opening found only in the transverse processes of cervical vertebrae

transverse process

paired bony processes that extends laterally from the vertebral arch of a vertebra

transverse plane

two-dimensional, horizontal plane that divides the body or organ into superior and inferior portions

transversospinales

muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae

transversus abdominis

deep layer of the abdomen that has fascicles arranged transversely around the abdomen

trapezoid

from the lateral side, the second of the four distal carpal bones; articulates with the scaphoid proximally, the second metacarpal distally, the trapezium laterally, and the capitate medially

trapezium

from the lateral side, the first of the four distal carpal bones; articulates with the scaphoid proximally, the first and second metacarpals distally, and the trapezoid medially

trapezius

muscle that stabilizes the upper part of the back

treppe

stepwise increase in contraction tension

tri

three

triad

the grouping of one T-tubule and two terminal cisternae

triad

the grouping of one T-tubule and two terminal cisternae

triceps brachii

three-headed muscle that extends the forearm

tricuspid valve

term used most often in clinical settings for the right atrioventricular valve

triglyceride

lipid compound composed of a glycerol molecule bonded with three fatty acid chains

triplet

consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid

triquetrum

from the lateral side, the third of the four proximal carpal bones; articulates with the lunate laterally, the hamate distally, and has a facet for the pisiform

trochlea

pulley-shaped region located medially at the distal end of the humerus; articulates at the elbow with the trochlear notch of the ulna

trochlear notch

large, C-shaped depression located on the anterior side of the proximal ulna; articulates at the elbow with the trochlea of the humerus

troponin

regulatory protein that binds to actin, tropomyosin, and calcium

tropomyosin

regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin

true vocal cord

one of the pair of folded, white membranes that have a free inner edge that oscillates as air passes through to produce sound

true ribs

vertebrosternal ribs 1–7 that attach via their costal cartilage directly to the sternum

trunk

large vessel that gives rise to smaller vessels

T-tubule

projection of the sarcolemma into the interior of the cell

T-tubule

projection of the sarcolemma into the interior of the cell