{"id":629,"date":"2015-10-28T15:55:57","date_gmt":"2015-10-28T19:55:57","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/chapter\/17-1-sensory-processes\/"},"modified":"2021-02-26T17:45:51","modified_gmt":"2021-02-26T22:45:51","slug":"17-1-sensory-processes","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/chapter\/17-1-sensory-processes\/","title":{"raw":"17.1\u00a0Sensory Processes","rendered":"17.1\u00a0Sensory Processes"},"content":{"raw":"<div class=\"titlepage\">\r\n<div class=\"abstract\">\r\n<div class=\"bcc-box bcc-highlight\">\r\n<h3>Learning Objectives<\/h3>\r\nBy the end of this section, you will be able to:\r\n<div class=\"itemizedlist\">\r\n<ul class=\"itemizedlist\">\r\n \t<li class=\"listitem\">Identify the general and special senses in humans<\/li>\r\n \t<li class=\"listitem\">Describe three important steps in sensory perception<\/li>\r\n \t<li class=\"listitem\">Explain the concept of just-noticeable difference in sensory perception<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<span id=\"m44754-fs-idp48827584\"> <\/span>Senses provide information about the body and its environment. Humans have five special senses: olfaction (smell), gustation (taste), equilibrium (balance and body position), vision, and hearing. Additionally, we possess general senses, also called somatosensation, which respond to stimuli like temperature, pain, pressure, and vibration. <span id=\"m44754-autoid-cnx2dbk-id1280082\"> <\/span><strong>Vestibular sensation<\/strong>, which is an organism\u2019s sense of spatial orientation and balance, <span id=\"m44754-autoid-cnx2dbk-id1280085\"> <\/span><strong>proprioception<\/strong> (position of bones, joints, and muscles), and the sense of limb position that is used to track <span id=\"m44754-autoid-cnx2dbk-id1280090\"> <\/span><strong>kinesthesia<\/strong> (limb movement) are part of somatosensation. Although the sensory systems associated with these senses are very different, all share a common function: to convert a stimulus (such as light, or sound, or the position of the body) into an electrical signal in the nervous system. This process is called <strong><span id=\"m44754-autoid-cnx2dbk-id1280096\"> <\/span>sensory transduction<\/strong>.\r\n\r\n<span id=\"m44754-fs-idp111589088\"> <\/span>There are two broad types of cellular systems that perform sensory transduction. In one, a neuron works with a <span id=\"m44754-autoid-cnx2dbk-id1280106\"> <\/span><strong>sensory receptor<\/strong>, a cell, or cell process that is specialized to engage with and detect a specific stimulus. Stimulation of the sensory receptor activates the associated afferent neuron, which carries information about the stimulus to the central nervous system. In the second type of sensory transduction, a sensory nerve ending responds to a stimulus in the internal or external environment: this neuron constitutes the sensory receptor. Free nerve endings can be stimulated by several different stimuli, thus showing little receptor specificity. For example, pain receptors in your gums and teeth may be stimulated by temperature changes, chemical stimulation, or pressure.\r\n<div class=\"section\" title=\"Reception\">\r\n<div class=\"titlepage\">\r\n<div>\r\n<div>\r\n<h3 id=\"m44754-fs-idp93566032\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Reception<\/span><\/span><\/h3>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<span id=\"m44754-fs-idp166398320\"> <\/span>The first step in sensation is <span id=\"m44754-autoid-cnx2dbk-id1280129\"> <\/span><strong>reception<\/strong>\r\n\r\n<\/div>\r\n, which is the activation of sensory receptors by stimuli such as mechanical stimuli (being bent or squished, for example), chemicals, or temperature. The receptor can then respond to the stimuli. The region in space in which a given sensory receptor can respond to a stimulus, be it far away or in contact with the body, is that receptor\u2019s <span id=\"m44754-autoid-cnx2dbk-id1247278\"> <\/span><strong>receptive<\/strong> <span id=\"m44754-autoid-cnx2dbk-id1247280\"> <\/span>field. Think for a moment about the differences in receptive fields for the different senses. For the sense of touch, a stimulus must come into contact with body. For the sense of hearing, a stimulus can be a moderate distance away (some baleen whale sounds can propagate for many kilometers). For vision, a stimulus can be very far away; for example, the visual system perceives light from stars at enormous distances.\r\n<div class=\"section\" title=\"Transduction\">\r\n<div class=\"titlepage\">\r\n<div>\r\n<div>\r\n<h3 id=\"m44754-fs-idp44066992\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Transduction<\/span><\/span><\/h3>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<span id=\"m44754-fs-idm23928880\"> <\/span>The most fundamental function of a sensory system is the translation of a sensory signal to an electrical signal in the nervous system. This takes place at the sensory receptor, and the change in electrical potential that is produced is called the <span id=\"m44754-autoid-cnx2dbk-id1247305\"> <\/span><strong>receptor potential<\/strong>. How is sensory input, such as pressure on the skin, changed to a receptor potential? In this example, a type of receptor called a <span id=\"m44754-autoid-cnx2dbk-id1247310\"> <\/span><strong>mechanoreceptor<\/strong> (as shown in\r\n\r\n<\/div>\r\n<a class=\"xref target-figure\" title=\"Figure\u00a036.2.\u00a0\" href=\"#attachment_1188\">Figure 17.2<\/a>) possesses specialized membranes that respond to pressure. Disturbance of these dendrites by compressing them or bending them opens gated ion channels in the plasma membrane of the sensory neuron, changing its electrical potential. Recall that in the nervous system, a positive change of a neuron\u2019s electrical potential (also called the membrane potential), depolarizes the neuron. Receptor potentials are graded potentials: the magnitude of these graded (receptor) potentials varies with the strength of the stimulus. If the magnitude of depolarization is sufficient (that is, if membrane potential reaches a threshold), the neuron will fire an action potential. In most cases, the correct stimulus impinging on a sensory receptor will drive membrane potential in a positive direction, although for some receptors, such as those in the visual system, this is not always the case.\r\n\r\n[caption id=\"attachment_1188\" align=\"aligncenter\" width=\"500\"]<a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_36_01_01f.jpg\"><img class=\"wp-image-1188\" src=\"https:\/\/pressbooks.bccampus.ca\/knowinghome\/wp-content\/uploads\/sites\/1064\/2015\/10\/Figure_36_01_01f-1024x903-1.jpg\" alt=\"Figure_36_01_01f\" width=\"500\" height=\"441\" \/><\/a> Figure 17.2.\u00a0 (a) Mechanosensitive ion channels are gated ion channels that respond to mechanical deformation of the plasma membrane. A mechanosensitive channel is connected to the plasma membrane and the cytoskeleton by hair-like tethers. When pressure causes the extracellular matrix to move, the channel opens, allowing ions to enter or exit the cell. (b) Stereocilia in the human ear are connected to mechanosensitive ion channels. When a sound causes the stereocilia to move, mechanosensitive ion channels transduce the signal to the cochlear nerve.[\/caption]\r\n\r\n<span id=\"m44754-fs-idp205928160\"> <\/span>Sensory receptors for different senses are very different from each other, and they are specialized according to the type of stimulus they sense: they have receptor specificity. For example, touch receptors, light receptors, and sound receptors are each activated by different stimuli. Touch receptors are not sensitive to light or sound; they are sensitive only to touch or pressure. However, stimuli may be combined at higher levels in the brain, as happens with olfaction, contributing to our sense of taste.\r\n<div class=\"section\" title=\"Encoding and Transmission of Sensory Information\">\r\n<div class=\"titlepage\">\r\n<div>\r\n<div>\r\n<h2 id=\"m44754-fs-idp69084640\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Encoding and Transmission of Sensory Information<\/span><\/span><\/h2>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<span id=\"m44754-fs-idp78590960\"> <\/span>Four aspects of sensory information are encoded by sensory systems: the type of stimulus, the location of the stimulus in the receptive field, the duration of the stimulus, and the relative intensity of the stimulus. Thus, action potentials transmitted over a sensory receptor\u2019s afferent axons encode one type of stimulus, and this segregation of the senses is preserved in other sensory circuits. For example, auditory receptors transmit signals over their own dedicated system, and electrical activity in the axons of the auditory receptors will be interpreted by the brain as an auditory stimulus\u2014a sound.\r\n\r\n<span id=\"m44754-fs-idp171530400\"> <\/span>The intensity of a stimulus is often encoded in the rate of action potentials produced by the sensory receptor. Thus, an intense stimulus will produce a more rapid train of action potentials, and reducing the stimulus will likewise slow the rate of production of action potentials. A second way in which intensity is encoded is by the number of receptors activated. An intense stimulus might initiate action potentials in a large number of adjacent receptors, while a less intense stimulus might stimulate fewer receptors. Integration of sensory information begins as soon as the information is received in the CNS, and the brain will further process incoming signals.\r\n\r\n<\/div>\r\n<div class=\"section\" title=\"Perception\">\r\n<div class=\"titlepage\">\r\n<div>\r\n<div>\r\n<h2 id=\"m44754-fs-idp99711392\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Perception<\/span><\/span><\/h2>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<span id=\"m44754-autoid-cnx2dbk-id1247414\"> <\/span><strong>Perception<\/strong> is an individual\u2019s interpretation of a sensation. Although perception relies on the activation of sensory receptors, perception happens not at the level of the sensory receptor, but at higher levels in the nervous system, in the brain. The brain distinguishes sensory stimuli through a sensory pathway: action potentials from sensory receptors travel along neurons that are dedicated to a particular stimulus. These neurons are dedicated to that particular stimulus and synapse with particular neurons in the brain or spinal cord.\r\n\r\n<span id=\"m44754-fs-idp103757536\"> <\/span>All sensory signals, except those from the olfactory system, are transmitted though the central nervous system and are routed to the thalamus and to the appropriate region of the cortex. Recall that the thalamus is a structure in the forebrain that serves as a clearinghouse and relay station for sensory (as well as motor) signals. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex (<a class=\"xref target-figure\" title=\"Figure\u00a036.3.\u00a0\" href=\"#attachment_1189\">Figure 17.3<\/a>) dedicated to processing that particular sense.\r\n\r\n<span id=\"m44754-fs-idp40037520\"> <\/span>How are neural signals interpreted? Interpretation of sensory signals between individuals of the same species is largely similar, owing to the inherited similarity of their nervous systems; however, there are some individual differences. A good example of this is individual tolerances to a painful stimulus, such as dental pain, which certainly differ.\r\n\r\n[caption id=\"attachment_1189\" align=\"aligncenter\" width=\"600\"]<a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_36_01_02.jpg\"><img class=\"wp-image-1189\" src=\"https:\/\/pressbooks.bccampus.ca\/knowinghome\/wp-content\/uploads\/sites\/1064\/2020\/06\/Figure_36_01_02-1024x429-1.jpg\" alt=\"Figure_36_01_02\" width=\"600\" height=\"251\" \/><\/a> Figure 17.3.\u00a0 In humans, with the exception of olfaction, all sensory signals are routed from the (a) thalamus to (b) final processing regions in the cortex of the brain. (credit b: modification of work by Polina Tishina) Scientific Method Connection[\/caption]\r\n\r\n<div id=\"m44754-fig-ch36_01_02\" class=\"figure\" title=\"Figure\u00a036.3.\u00a0\">\r\n<div class=\"title\"><\/div>\r\n<div id=\"m44754-fs-idp37911744\" class=\"note scientific\">\r\n<div class=\"body\">\r\n<h2 class=\"title\" style=\"text-align: left;\">Just-Noticeable Difference<\/h2>\r\n<p title=\"Just-Noticeable Difference\">It is easy to differentiate between a one-pound bag of rice and a two-pound bag of rice. There is a one-pound difference, and one bag is twice as heavy as the other. However, would it be as easy to differentiate between a 20- and a 21-pound bag?<\/p>\r\n<span id=\"m44754-fs-idm32842976\"> <\/span><span class=\"bold\"><strong>Question:<\/strong><\/span> What is the smallest detectible weight difference between a one-pound bag of rice and a larger bag? What is the smallest detectible difference between a 20-pound bag and a larger bag? In both cases, at what weights are the differences detected? This smallest detectible difference in stimuli is known as the just-noticeable difference (JND).\r\n\r\n<span id=\"m44754-fs-idm34634560\"> <\/span><span class=\"bold\"><strong>Background:<\/strong><\/span> Research background literature on JND and on Weber\u2019s Law, a description of a proposed mathematical relationship between the overall magnitude of the stimulus and the JND. You will be testing JND of different weights of rice in bags. Choose a convenient increment that is to be stepped through while testing. For example, you could choose 10 percent increments between one and two pounds (1.1, 1.2, 1.3, 1.4, and so on) or 20 percent increments (1.2, 1.4, 1.6, and 1.8).\r\n\r\n<span id=\"m44754-fs-idp56639968\"> <\/span><span class=\"bold\"><strong>Hypothesis:<\/strong><\/span> Develop a hypothesis about JND in terms of percentage of the whole weight being tested (such as \u201cthe JND between the two small bags and between the two large bags is proportionally the same,\u201d or \u201c. . . is not proportionally the same.\u201d) So, for the first hypothesis, if the JND between the one-pound bag and a larger bag is 0.2 pounds (that is, 20 percent; 1.0 pound feels the same as 1.1 pounds, but 1.0 pound feels less than 1.2 pounds), then the JND between the 20-pound bag and a larger bag will also be 20 percent. (So, 20 pounds feels the same as 22 pounds or 23 pounds, but 20 pounds feels less than 24 pounds.)\r\n\r\n<span id=\"m44754-fs-idp95698304\"> <\/span><span class=\"bold\"><strong>Test the hypothesis:<\/strong><\/span> Enlist 24 participants, and split them into two groups of 12. To set up the demonstration, assuming a 10 percent increment was selected, have the first group be the one-pound group. As a counter-balancing measure against a systematic error, however, six of the first group will compare one pound to two pounds, and step down in weight (1.0 to 2.0, 1.0 to 1.9, and so on.), while the other six will step up (1.0 to 1.1, 1.0 to 1.2, and so on). Apply the same principle to the 20-pound group (20 to 40, 20 to 38, and so on, and 20 to 22, 20 to 24, and so on). Given the large difference between 20 and 40 pounds, you may wish to use 30 pounds as your larger weight. In any case, use two weights that are easily detectable as different.\r\n\r\n<span id=\"m44754-fs-idm48857536\"> <\/span><span class=\"bold\"><strong>Record the observations:<\/strong><\/span> Record the data in a table similar to the table below. For the one-pound and 20-pound groups (base weights) record a plus sign (+) for each participant that detects a difference between the base weight and the step weight. Record a minus sign (-) for each participant that finds no difference. If one-tenth steps were not used, then replace the steps in the \u201cStep Weight\u201d columns with the step you are using.\r\n<div id=\"m44754-tab-ch36_00_01\" class=\"table\">\r\n<table cellspacing=\"0\" cellpadding=\"0\"><caption><span class=\"cnx-gentext-caption cnx-gentext-t\">Table 17<\/span><span class=\"cnx-gentext-caption cnx-gentext-n\">.1.\u00a0Results of JND Testing (+ = difference; \u2013 = no difference)<\/span><\/caption>\r\n<thead valign=\"bottom\">\r\n<tr>\r\n<th>Step Weight<\/th>\r\n<th>One pound<\/th>\r\n<th>20 pounds<\/th>\r\n<th>Step Weight<\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody valign=\"top\">\r\n<tr>\r\n<td>1.1<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>22<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.2<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>24<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.3<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>26<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.4<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>28<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.5<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>30<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.6<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>32<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.7<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>34<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.8<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>36<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1.9<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>38<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>2.0<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<td>40<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/div>\r\n<span id=\"m44754-fs-idp49758240\"> <\/span><span class=\"bold\"><strong>Analyze the data\/report the results:<\/strong><\/span> What step weight did all participants find to be equal with one-pound base weight? What about the 20-pound group?\r\n\r\n<span id=\"m44754-fs-idp173809904\"> <\/span><span class=\"bold\"><strong>Draw a conclusion:<\/strong><\/span> Did the data support the hypothesis? Are the final weights proportionally the same? If not, why not? Do the findings adhere to Weber\u2019s Law? Weber\u2019s Law states that the concept that a just-noticeable difference in a stimulus is proportional to the magnitude of the original stimulus.\r\n<h2>\u00a0Summary<\/h2>\r\nA sensory activation occurs when a physical or chemical stimulus is processed into a neural signal (sensory transduction) by a sensory receptor. Perception is an individual interpretation of a sensation and is a brain function. Humans have special senses: olfaction, gustation, equilibrium, and hearing, plus the general senses of somatosensation.\r\n\r\n<span id=\"m44754-fs-idp45026640\"> <\/span>Sensory receptors are either specialized cells associated with sensory neurons or the specialized ends of sensory neurons that are a part of the peripheral nervous system, and they are used to receive information about the environment (internal or external). Each sensory receptor is modified for the type of stimulus it detects. For example, neither gustatory receptors nor auditory receptors are sensitive to light. Each sensory receptor is responsive to stimuli within a specific region in space, which is known as that receptor\u2019s receptive field. The most fundamental function of a sensory system is the translation of a sensory signal to an electrical signal in the nervous system.\r\n\r\n<span id=\"m44754-fs-idp160588160\"> <\/span>All sensory signals, except those from the olfactory system, enter the central nervous system and are routed to the thalamus. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex dedicated to processing that particular sense.\r\n<div class=\"textbox exercises\">\r\n<h3>Exercises<\/h3>\r\n<ol>\r\n \t<li>Which of the following statements about mechanoreceptors is false?\r\n<ol>\r\n \t<li>Pacini corpuscles are found in both glabrous and hairy skin.<\/li>\r\n \t<li>Merkel\u2019s disks are abundant on the fingertips and lips.<\/li>\r\n \t<li>Ruffini endings are encapsulated mechanoreceptors.<\/li>\r\n \t<li>Meissner\u2019s corpuscles extend into the lower dermis.<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>Where does perception occur?\r\n<ol>\r\n \t<li>spinal cord<\/li>\r\n \t<li>cerebral cortex<\/li>\r\n \t<li>receptors<\/li>\r\n \t<li>thalamus<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li><span id=\"m44754-fs-idp38470112\">If a person\u2019s cold receptors no longer convert cold stimuli into sensory signals, that person has a problem with the process of ________.<\/span>\r\n<ol>\r\n \t<li>reception<\/li>\r\n \t<li>transmission<\/li>\r\n \t<li>perception<\/li>\r\n \t<li>transduction<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li><span id=\"m44754-fs-idm24552512\"><span id=\"m44754-fs-idp208362224\"><\/span>After somatosensory transduction, the sensory signal travels through the brain as a(n) _____ signal.<\/span>\r\n<ol>\r\n \t<li>electrical<\/li>\r\n \t<li>pressure<\/li>\r\n \t<li>optical<\/li>\r\n \t<li>thermal<\/li>\r\n<\/ol>\r\n<\/li>\r\n<\/ol>\r\n<strong>Answers<\/strong>\r\n<ol>\r\n \t<li>D<\/li>\r\n \t<li>B<\/li>\r\n \t<li>D<\/li>\r\n \t<li>A<\/li>\r\n<\/ol>\r\n<\/div>\r\n<div id=\"id790893\" class=\"glossary\" title=\"Glossary\">\r\n<div class=\"section\" title=\"Higher Processing\">\r\n<div id=\"m44761-fs-idp51526480\" class=\"note interactive\">\r\n<div class=\"body\"><\/div>\r\n<\/div>\r\n<div class=\"glossary\" title=\"Glossary\">\r\n<div class=\"titlepage\">\r\n<div class=\"bcc-box bcc-success\">\r\n<h3>Glossary<\/h3>\r\n<dl>\r\n \t<dt><strong>kinesthesia<\/strong><\/dt>\r\n \t<dd>sense of body movement<\/dd>\r\n \t<dt><strong>mechanoreceptor<\/strong><\/dt>\r\n \t<dd>sensory receptor modified to respond to mechanical disturbance such as being bent, touch, pressure, motion, and sound<\/dd>\r\n \t<dt><strong>perception<\/strong><\/dt>\r\n \t<dd>individual interpretation of a sensation; a brain function<\/dd>\r\n \t<dt><strong>proprioception<\/strong><\/dt>\r\n \t<dd>sense of limb position; used to track kinesthesia<\/dd>\r\n \t<dt><strong>reception<\/strong><\/dt>\r\n \t<dd>receipt of a signal (such as light or sound) by sensory receptors<\/dd>\r\n \t<dt><strong>receptive field<\/strong><\/dt>\r\n \t<dd>region in space in which a stimulus can activate a given sensory receptor<\/dd>\r\n \t<dt><strong>receptor potential<\/strong><\/dt>\r\n \t<dd>membrane potential in a sensory receptor in response to detection of a stimulus<\/dd>\r\n \t<dt><strong>sensory receptor<\/strong><\/dt>\r\n \t<dd>specialized neuron or other cells associated with a neuron that is modified to receive specific sensory input<\/dd>\r\n \t<dt><strong>sensory transduction<\/strong><\/dt>\r\n \t<dd>conversion of a sensory stimulus into electrical energy in the nervous system by a change in the membrane potential<\/dd>\r\n \t<dt><strong>vestibular sense<\/strong><\/dt>\r\n \t<dd>sense of spatial orientation and balance<\/dd>\r\n<\/dl>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>","rendered":"<div class=\"titlepage\">\n<div class=\"abstract\">\n<div class=\"bcc-box bcc-highlight\">\n<h3>Learning Objectives<\/h3>\n<p>By the end of this section, you will be able to:<\/p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">Identify the general and special senses in humans<\/li>\n<li class=\"listitem\">Describe three important steps in sensory perception<\/li>\n<li class=\"listitem\">Explain the concept of just-noticeable difference in sensory perception<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44754-fs-idp48827584\"> <\/span>Senses provide information about the body and its environment. Humans have five special senses: olfaction (smell), gustation (taste), equilibrium (balance and body position), vision, and hearing. Additionally, we possess general senses, also called somatosensation, which respond to stimuli like temperature, pain, pressure, and vibration. <span id=\"m44754-autoid-cnx2dbk-id1280082\"> <\/span><strong>Vestibular sensation<\/strong>, which is an organism\u2019s sense of spatial orientation and balance, <span id=\"m44754-autoid-cnx2dbk-id1280085\"> <\/span><strong>proprioception<\/strong> (position of bones, joints, and muscles), and the sense of limb position that is used to track <span id=\"m44754-autoid-cnx2dbk-id1280090\"> <\/span><strong>kinesthesia<\/strong> (limb movement) are part of somatosensation. Although the sensory systems associated with these senses are very different, all share a common function: to convert a stimulus (such as light, or sound, or the position of the body) into an electrical signal in the nervous system. This process is called <strong><span id=\"m44754-autoid-cnx2dbk-id1280096\"> <\/span>sensory transduction<\/strong>.<\/p>\n<p><span id=\"m44754-fs-idp111589088\"> <\/span>There are two broad types of cellular systems that perform sensory transduction. In one, a neuron works with a <span id=\"m44754-autoid-cnx2dbk-id1280106\"> <\/span><strong>sensory receptor<\/strong>, a cell, or cell process that is specialized to engage with and detect a specific stimulus. Stimulation of the sensory receptor activates the associated afferent neuron, which carries information about the stimulus to the central nervous system. In the second type of sensory transduction, a sensory nerve ending responds to a stimulus in the internal or external environment: this neuron constitutes the sensory receptor. Free nerve endings can be stimulated by several different stimuli, thus showing little receptor specificity. For example, pain receptors in your gums and teeth may be stimulated by temperature changes, chemical stimulation, or pressure.<\/p>\n<div class=\"section\" title=\"Reception\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h3 id=\"m44754-fs-idp93566032\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Reception<\/span><\/span><\/h3>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44754-fs-idp166398320\"> <\/span>The first step in sensation is <span id=\"m44754-autoid-cnx2dbk-id1280129\"> <\/span><strong>reception<\/strong><\/p>\n<\/div>\n<p>, which is the activation of sensory receptors by stimuli such as mechanical stimuli (being bent or squished, for example), chemicals, or temperature. The receptor can then respond to the stimuli. The region in space in which a given sensory receptor can respond to a stimulus, be it far away or in contact with the body, is that receptor\u2019s <span id=\"m44754-autoid-cnx2dbk-id1247278\"> <\/span><strong>receptive<\/strong> <span id=\"m44754-autoid-cnx2dbk-id1247280\"> <\/span>field. Think for a moment about the differences in receptive fields for the different senses. For the sense of touch, a stimulus must come into contact with body. For the sense of hearing, a stimulus can be a moderate distance away (some baleen whale sounds can propagate for many kilometers). For vision, a stimulus can be very far away; for example, the visual system perceives light from stars at enormous distances.<\/p>\n<div class=\"section\" title=\"Transduction\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h3 id=\"m44754-fs-idp44066992\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Transduction<\/span><\/span><\/h3>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44754-fs-idm23928880\"> <\/span>The most fundamental function of a sensory system is the translation of a sensory signal to an electrical signal in the nervous system. This takes place at the sensory receptor, and the change in electrical potential that is produced is called the <span id=\"m44754-autoid-cnx2dbk-id1247305\"> <\/span><strong>receptor potential<\/strong>. How is sensory input, such as pressure on the skin, changed to a receptor potential? In this example, a type of receptor called a <span id=\"m44754-autoid-cnx2dbk-id1247310\"> <\/span><strong>mechanoreceptor<\/strong> (as shown in<\/p>\n<\/div>\n<p><a class=\"xref target-figure\" title=\"Figure\u00a036.2.\u00a0\" href=\"#attachment_1188\">Figure 17.2<\/a>) possesses specialized membranes that respond to pressure. Disturbance of these dendrites by compressing them or bending them opens gated ion channels in the plasma membrane of the sensory neuron, changing its electrical potential. Recall that in the nervous system, a positive change of a neuron\u2019s electrical potential (also called the membrane potential), depolarizes the neuron. Receptor potentials are graded potentials: the magnitude of these graded (receptor) potentials varies with the strength of the stimulus. If the magnitude of depolarization is sufficient (that is, if membrane potential reaches a threshold), the neuron will fire an action potential. In most cases, the correct stimulus impinging on a sensory receptor will drive membrane potential in a positive direction, although for some receptors, such as those in the visual system, this is not always the case.<\/p>\n<figure id=\"attachment_1188\" aria-describedby=\"caption-attachment-1188\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_36_01_01f.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1188\" src=\"https:\/\/pressbooks.bccampus.ca\/knowinghome\/wp-content\/uploads\/sites\/1064\/2015\/10\/Figure_36_01_01f-1024x903-1.jpg\" alt=\"Figure_36_01_01f\" width=\"500\" height=\"441\" \/><\/a><figcaption id=\"caption-attachment-1188\" class=\"wp-caption-text\">Figure 17.2.\u00a0 (a) Mechanosensitive ion channels are gated ion channels that respond to mechanical deformation of the plasma membrane. A mechanosensitive channel is connected to the plasma membrane and the cytoskeleton by hair-like tethers. When pressure causes the extracellular matrix to move, the channel opens, allowing ions to enter or exit the cell. (b) Stereocilia in the human ear are connected to mechanosensitive ion channels. When a sound causes the stereocilia to move, mechanosensitive ion channels transduce the signal to the cochlear nerve.<\/figcaption><\/figure>\n<p><span id=\"m44754-fs-idp205928160\"> <\/span>Sensory receptors for different senses are very different from each other, and they are specialized according to the type of stimulus they sense: they have receptor specificity. For example, touch receptors, light receptors, and sound receptors are each activated by different stimuli. Touch receptors are not sensitive to light or sound; they are sensitive only to touch or pressure. However, stimuli may be combined at higher levels in the brain, as happens with olfaction, contributing to our sense of taste.<\/p>\n<div class=\"section\" title=\"Encoding and Transmission of Sensory Information\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44754-fs-idp69084640\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Encoding and Transmission of Sensory Information<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44754-fs-idp78590960\"> <\/span>Four aspects of sensory information are encoded by sensory systems: the type of stimulus, the location of the stimulus in the receptive field, the duration of the stimulus, and the relative intensity of the stimulus. Thus, action potentials transmitted over a sensory receptor\u2019s afferent axons encode one type of stimulus, and this segregation of the senses is preserved in other sensory circuits. For example, auditory receptors transmit signals over their own dedicated system, and electrical activity in the axons of the auditory receptors will be interpreted by the brain as an auditory stimulus\u2014a sound.<\/p>\n<p><span id=\"m44754-fs-idp171530400\"> <\/span>The intensity of a stimulus is often encoded in the rate of action potentials produced by the sensory receptor. Thus, an intense stimulus will produce a more rapid train of action potentials, and reducing the stimulus will likewise slow the rate of production of action potentials. A second way in which intensity is encoded is by the number of receptors activated. An intense stimulus might initiate action potentials in a large number of adjacent receptors, while a less intense stimulus might stimulate fewer receptors. Integration of sensory information begins as soon as the information is received in the CNS, and the brain will further process incoming signals.<\/p>\n<\/div>\n<div class=\"section\" title=\"Perception\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44754-fs-idp99711392\" style=\"text-align: left;\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Perception<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44754-autoid-cnx2dbk-id1247414\"> <\/span><strong>Perception<\/strong> is an individual\u2019s interpretation of a sensation. Although perception relies on the activation of sensory receptors, perception happens not at the level of the sensory receptor, but at higher levels in the nervous system, in the brain. The brain distinguishes sensory stimuli through a sensory pathway: action potentials from sensory receptors travel along neurons that are dedicated to a particular stimulus. These neurons are dedicated to that particular stimulus and synapse with particular neurons in the brain or spinal cord.<\/p>\n<p><span id=\"m44754-fs-idp103757536\"> <\/span>All sensory signals, except those from the olfactory system, are transmitted though the central nervous system and are routed to the thalamus and to the appropriate region of the cortex. Recall that the thalamus is a structure in the forebrain that serves as a clearinghouse and relay station for sensory (as well as motor) signals. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex (<a class=\"xref target-figure\" title=\"Figure\u00a036.3.\u00a0\" href=\"#attachment_1189\">Figure 17.3<\/a>) dedicated to processing that particular sense.<\/p>\n<p><span id=\"m44754-fs-idp40037520\"> <\/span>How are neural signals interpreted? Interpretation of sensory signals between individuals of the same species is largely similar, owing to the inherited similarity of their nervous systems; however, there are some individual differences. A good example of this is individual tolerances to a painful stimulus, such as dental pain, which certainly differ.<\/p>\n<figure id=\"attachment_1189\" aria-describedby=\"caption-attachment-1189\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_36_01_02.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1189\" src=\"https:\/\/pressbooks.bccampus.ca\/knowinghome\/wp-content\/uploads\/sites\/1064\/2020\/06\/Figure_36_01_02-1024x429-1.jpg\" alt=\"Figure_36_01_02\" width=\"600\" height=\"251\" \/><\/a><figcaption id=\"caption-attachment-1189\" class=\"wp-caption-text\">Figure 17.3.\u00a0 In humans, with the exception of olfaction, all sensory signals are routed from the (a) thalamus to (b) final processing regions in the cortex of the brain. (credit b: modification of work by Polina Tishina) Scientific Method Connection<\/figcaption><\/figure>\n<div id=\"m44754-fig-ch36_01_02\" class=\"figure\" title=\"Figure\u00a036.3.\u00a0\">\n<div class=\"title\"><\/div>\n<div id=\"m44754-fs-idp37911744\" class=\"note scientific\">\n<div class=\"body\">\n<h2 class=\"title\" style=\"text-align: left;\">Just-Noticeable Difference<\/h2>\n<p title=\"Just-Noticeable Difference\">It is easy to differentiate between a one-pound bag of rice and a two-pound bag of rice. There is a one-pound difference, and one bag is twice as heavy as the other. However, would it be as easy to differentiate between a 20- and a 21-pound bag?<\/p>\n<p><span id=\"m44754-fs-idm32842976\"> <\/span><span class=\"bold\"><strong>Question:<\/strong><\/span> What is the smallest detectible weight difference between a one-pound bag of rice and a larger bag? What is the smallest detectible difference between a 20-pound bag and a larger bag? In both cases, at what weights are the differences detected? This smallest detectible difference in stimuli is known as the just-noticeable difference (JND).<\/p>\n<p><span id=\"m44754-fs-idm34634560\"> <\/span><span class=\"bold\"><strong>Background:<\/strong><\/span> Research background literature on JND and on Weber\u2019s Law, a description of a proposed mathematical relationship between the overall magnitude of the stimulus and the JND. You will be testing JND of different weights of rice in bags. Choose a convenient increment that is to be stepped through while testing. For example, you could choose 10 percent increments between one and two pounds (1.1, 1.2, 1.3, 1.4, and so on) or 20 percent increments (1.2, 1.4, 1.6, and 1.8).<\/p>\n<p><span id=\"m44754-fs-idp56639968\"> <\/span><span class=\"bold\"><strong>Hypothesis:<\/strong><\/span> Develop a hypothesis about JND in terms of percentage of the whole weight being tested (such as \u201cthe JND between the two small bags and between the two large bags is proportionally the same,\u201d or \u201c. . . is not proportionally the same.\u201d) So, for the first hypothesis, if the JND between the one-pound bag and a larger bag is 0.2 pounds (that is, 20 percent; 1.0 pound feels the same as 1.1 pounds, but 1.0 pound feels less than 1.2 pounds), then the JND between the 20-pound bag and a larger bag will also be 20 percent. (So, 20 pounds feels the same as 22 pounds or 23 pounds, but 20 pounds feels less than 24 pounds.)<\/p>\n<p><span id=\"m44754-fs-idp95698304\"> <\/span><span class=\"bold\"><strong>Test the hypothesis:<\/strong><\/span> Enlist 24 participants, and split them into two groups of 12. To set up the demonstration, assuming a 10 percent increment was selected, have the first group be the one-pound group. As a counter-balancing measure against a systematic error, however, six of the first group will compare one pound to two pounds, and step down in weight (1.0 to 2.0, 1.0 to 1.9, and so on.), while the other six will step up (1.0 to 1.1, 1.0 to 1.2, and so on). Apply the same principle to the 20-pound group (20 to 40, 20 to 38, and so on, and 20 to 22, 20 to 24, and so on). Given the large difference between 20 and 40 pounds, you may wish to use 30 pounds as your larger weight. In any case, use two weights that are easily detectable as different.<\/p>\n<p><span id=\"m44754-fs-idm48857536\"> <\/span><span class=\"bold\"><strong>Record the observations:<\/strong><\/span> Record the data in a table similar to the table below. For the one-pound and 20-pound groups (base weights) record a plus sign (+) for each participant that detects a difference between the base weight and the step weight. Record a minus sign (-) for each participant that finds no difference. If one-tenth steps were not used, then replace the steps in the \u201cStep Weight\u201d columns with the step you are using.<\/p>\n<div id=\"m44754-tab-ch36_00_01\" class=\"table\">\n<table cellpadding=\"0\" style=\"border-spacing: 0px;\">\n<caption><span class=\"cnx-gentext-caption cnx-gentext-t\">Table 17<\/span><span class=\"cnx-gentext-caption cnx-gentext-n\">.1.\u00a0Results of JND Testing (+ = difference; \u2013 = no difference)<\/span><\/caption>\n<thead valign=\"bottom\">\n<tr>\n<th>Step Weight<\/th>\n<th>One pound<\/th>\n<th>20 pounds<\/th>\n<th>Step Weight<\/th>\n<\/tr>\n<\/thead>\n<tbody valign=\"top\">\n<tr>\n<td>1.1<\/td>\n<td><\/td>\n<td><\/td>\n<td>22<\/td>\n<\/tr>\n<tr>\n<td>1.2<\/td>\n<td><\/td>\n<td><\/td>\n<td>24<\/td>\n<\/tr>\n<tr>\n<td>1.3<\/td>\n<td><\/td>\n<td><\/td>\n<td>26<\/td>\n<\/tr>\n<tr>\n<td>1.4<\/td>\n<td><\/td>\n<td><\/td>\n<td>28<\/td>\n<\/tr>\n<tr>\n<td>1.5<\/td>\n<td><\/td>\n<td><\/td>\n<td>30<\/td>\n<\/tr>\n<tr>\n<td>1.6<\/td>\n<td><\/td>\n<td><\/td>\n<td>32<\/td>\n<\/tr>\n<tr>\n<td>1.7<\/td>\n<td><\/td>\n<td><\/td>\n<td>34<\/td>\n<\/tr>\n<tr>\n<td>1.8<\/td>\n<td><\/td>\n<td><\/td>\n<td>36<\/td>\n<\/tr>\n<tr>\n<td>1.9<\/td>\n<td><\/td>\n<td><\/td>\n<td>38<\/td>\n<\/tr>\n<tr>\n<td>2.0<\/td>\n<td><\/td>\n<td><\/td>\n<td>40<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p><span id=\"m44754-fs-idp49758240\"> <\/span><span class=\"bold\"><strong>Analyze the data\/report the results:<\/strong><\/span> What step weight did all participants find to be equal with one-pound base weight? What about the 20-pound group?<\/p>\n<p><span id=\"m44754-fs-idp173809904\"> <\/span><span class=\"bold\"><strong>Draw a conclusion:<\/strong><\/span> Did the data support the hypothesis? Are the final weights proportionally the same? If not, why not? Do the findings adhere to Weber\u2019s Law? Weber\u2019s Law states that the concept that a just-noticeable difference in a stimulus is proportional to the magnitude of the original stimulus.<\/p>\n<h2>\u00a0Summary<\/h2>\n<p>A sensory activation occurs when a physical or chemical stimulus is processed into a neural signal (sensory transduction) by a sensory receptor. Perception is an individual interpretation of a sensation and is a brain function. Humans have special senses: olfaction, gustation, equilibrium, and hearing, plus the general senses of somatosensation.<\/p>\n<p><span id=\"m44754-fs-idp45026640\"> <\/span>Sensory receptors are either specialized cells associated with sensory neurons or the specialized ends of sensory neurons that are a part of the peripheral nervous system, and they are used to receive information about the environment (internal or external). Each sensory receptor is modified for the type of stimulus it detects. For example, neither gustatory receptors nor auditory receptors are sensitive to light. Each sensory receptor is responsive to stimuli within a specific region in space, which is known as that receptor\u2019s receptive field. The most fundamental function of a sensory system is the translation of a sensory signal to an electrical signal in the nervous system.<\/p>\n<p><span id=\"m44754-fs-idp160588160\"> <\/span>All sensory signals, except those from the olfactory system, enter the central nervous system and are routed to the thalamus. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex dedicated to processing that particular sense.<\/p>\n<div class=\"textbox exercises\">\n<h3>Exercises<\/h3>\n<ol>\n<li>Which of the following statements about mechanoreceptors is false?\n<ol>\n<li>Pacini corpuscles are found in both glabrous and hairy skin.<\/li>\n<li>Merkel\u2019s disks are abundant on the fingertips and lips.<\/li>\n<li>Ruffini endings are encapsulated mechanoreceptors.<\/li>\n<li>Meissner\u2019s corpuscles extend into the lower dermis.<\/li>\n<\/ol>\n<\/li>\n<li>Where does perception occur?\n<ol>\n<li>spinal cord<\/li>\n<li>cerebral cortex<\/li>\n<li>receptors<\/li>\n<li>thalamus<\/li>\n<\/ol>\n<\/li>\n<li><span id=\"m44754-fs-idp38470112\">If a person\u2019s cold receptors no longer convert cold stimuli into sensory signals, that person has a problem with the process of ________.<\/span>\n<ol>\n<li>reception<\/li>\n<li>transmission<\/li>\n<li>perception<\/li>\n<li>transduction<\/li>\n<\/ol>\n<\/li>\n<li><span id=\"m44754-fs-idm24552512\"><span id=\"m44754-fs-idp208362224\"><\/span>After somatosensory transduction, the sensory signal travels through the brain as a(n) _____ signal.<\/span>\n<ol>\n<li>electrical<\/li>\n<li>pressure<\/li>\n<li>optical<\/li>\n<li>thermal<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><strong>Answers<\/strong><\/p>\n<ol>\n<li>D<\/li>\n<li>B<\/li>\n<li>D<\/li>\n<li>A<\/li>\n<\/ol>\n<\/div>\n<div id=\"id790893\" class=\"glossary\" title=\"Glossary\">\n<div class=\"section\" title=\"Higher Processing\">\n<div id=\"m44761-fs-idp51526480\" class=\"note interactive\">\n<div class=\"body\"><\/div>\n<\/div>\n<div class=\"glossary\" title=\"Glossary\">\n<div class=\"titlepage\">\n<div class=\"bcc-box bcc-success\">\n<h3>Glossary<\/h3>\n<dl>\n<dt><strong>kinesthesia<\/strong><\/dt>\n<dd>sense of body movement<\/dd>\n<dt><strong>mechanoreceptor<\/strong><\/dt>\n<dd>sensory receptor modified to respond to mechanical disturbance such as being bent, touch, pressure, motion, and sound<\/dd>\n<dt><strong>perception<\/strong><\/dt>\n<dd>individual interpretation of a sensation; a brain function<\/dd>\n<dt><strong>proprioception<\/strong><\/dt>\n<dd>sense of limb position; used to track kinesthesia<\/dd>\n<dt><strong>reception<\/strong><\/dt>\n<dd>receipt of a signal (such as light or sound) by sensory receptors<\/dd>\n<dt><strong>receptive field<\/strong><\/dt>\n<dd>region in space in which a stimulus can activate a given sensory receptor<\/dd>\n<dt><strong>receptor potential<\/strong><\/dt>\n<dd>membrane potential in a sensory receptor in response to detection of a stimulus<\/dd>\n<dt><strong>sensory receptor<\/strong><\/dt>\n<dd>specialized neuron or other cells associated with a neuron that is modified to receive specific sensory input<\/dd>\n<dt><strong>sensory transduction<\/strong><\/dt>\n<dd>conversion of a sensory stimulus into electrical energy in the nervous system by a change in the membrane potential<\/dd>\n<dt><strong>vestibular sense<\/strong><\/dt>\n<dd>sense of spatial orientation and balance<\/dd>\n<\/dl>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"author":103,"menu_order":33,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-629","chapter","type-chapter","status-publish","hentry"],"part":1387,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapters\/629","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/wp\/v2\/users\/103"}],"version-history":[{"count":2,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapters\/629\/revisions"}],"predecessor-version":[{"id":1420,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapters\/629\/revisions\/1420"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/parts\/1387"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapters\/629\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/wp\/v2\/media?parent=629"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/pressbooks\/v2\/chapter-type?post=629"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/wp\/v2\/contributor?post=629"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/biologyh5p\/wp-json\/wp\/v2\/license?post=629"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}