{"id":6560,"date":"2026-06-03T14:16:45","date_gmt":"2026-06-03T18:16:45","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/?post_type=chapter&p=6560"},"modified":"2026-06-09T15:22:58","modified_gmt":"2026-06-09T19:22:58","slug":"blood-composition-and-blood-disorders","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/chapter\/blood-composition-and-blood-disorders\/","title":{"raw":"Section 10:\u00a0 Blood Composition and Blood Disorders","rendered":"Section 10:\u00a0 Blood Composition and Blood Disorders"},"content":{"raw":"

Blood Composition<\/strong><\/span><\/h3>\r\n

Blood is fluid connective tissue<\/strong> with a liquid extracellular matrix called plasma.<\/strong>\u00a0 The formed elements<\/strong> are the cellular components:\u00a0 RBCs, WBCs, and platelets.\u00a0 If blood is allowed to settle by weight:<\/p>\r\n\r\n

    \r\n \t
  1. Plasma<\/strong> (~55% by volume) rises to the top;<\/li>\r\n \t
  2. Buffy coat<\/strong> (thin white layer of leukocytes (WBCs) and platelets, <1% forms in the middle); and<\/li>\r\n \t
  3. Erythrocytes<\/strong> (~41-45%) form the bottom dark red layer.<\/li>\r\n<\/ol>\r\nPlasma<\/strong> is a yellowish fluid and contains water, electrolytes (Na+<\/sup>, K+<\/sup>, Ca2+<\/sup>, Mg2+<\/sup>, Cl-<\/sup>, HCO3<\/sub>-<\/sup>, HPO4<\/sub>-<\/sup>, SO4<\/sub>2-<\/sup>), dissolved gases, amino acids, fatty acids, glycerides, cholesterol, glucose, hormones, organic wastes (urea, uric acid, creatinine, bilirubin) and proteins.\r\n\r\nIt is likely not surprising that interstitial fluid<\/strong> (the fluid between tissue cells of the body) is very similar in composition to plasma as an equilibrium does exist particularly for small water soluble ions and molecules.\u00a0 In comparison with plasma, interstitial fluid contains similar concentrations of water, electrolytes, dissolved gases, amino acids and hormones.\u00a0 However, plasma<\/strong> contains many dissolved proteins, whereas interstitial fluid does not.\r\n\r\n[caption id=\"attachment_2340\" align=\"alignnone\" width=\"234\"]\"A<\/a> A bag containing one unit of fresh frozen plasma.\u00a0 Donated plasma can be used:\u00a0 (1) for replacing lost blood volume due to trauma or burns, (2) extracting specific proteins (e.g., clotting factors, antibodies, albumin) in order to treat bleeding disorders, increase protection in immunocompromised patients, and (3) support liver function or manage fluid loss.[\/caption]\r\n

    Plasma Proteins<\/strong><\/span><\/h3>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
    Albumin (60% of plasma protein)<\/strong><\/span><\/td>\r\nProduced in the liver.<\/strong>\u00a0 Most abundant plasma protein.\r\n\r\nTransports lipid-soluble substances (fatty acids, steroid hormones).\r\n\r\nResponsible for most of the blood's osmotic force<\/strong>.<\/td>\r\n<\/tr>\r\n
    Globulins (35% of plasma proteins)<\/strong><\/span><\/td>\r\nInclude antibodies (immunoglobulins)<\/strong> produced by B cells, and liver-produced<\/strong> transport globulins that carry vitamins, lipids, metal ions, and hormones (e.g.,\u00a0 sex hormone-binding globulins, thyroxine-binding globulin, and cortisol-binding globulin).<\/strong><\/td>\r\n<\/tr>\r\n
    \u00a0C-reactive proteins (CRP)<\/strong><\/span><\/td>\r\nProduced by the liver;<\/strong> bind to dead cells and bacteria to activate the complement system<\/strong>.\r\n\r\nCRP serum levels correlate with the extent of tissue damage and inflammation.<\/td>\r\n<\/tr>\r\n
    \u00a0Fibrinogen & prothrombin (4%)<\/strong><\/span><\/td>\r\nProduced in the liver;<\/strong> involved in blood clotting.\u00a0 <\/strong>\r\n\r\nRequire Vitamin K <\/strong>during synthesis.<\/td>\r\n<\/tr>\r\n
    \u00a0Complement proteins<\/strong><\/span><\/td>\r\nProduced by the liver;<\/strong> act as opsonins, form MAC complexes, and stimulate mast cell activity.<\/td>\r\n<\/tr>\r\n
    \u00a0Lipoproteins<\/strong><\/span><\/td>\r\nProduced in the liver,<\/strong> transport triglycerides and cholesterol in the blood (e.g., high- and low- density lipoproteins, HDLs<\/strong> and LDLs)<\/strong>.<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n
    \r\n

    Hormones<\/p>\r\n\r\n<\/header>\r\n

    \r\n\r\nHormones are important signalling molecules that travel the bloodstream and regulate complex biological processes, growth, development, maturation, and behaviour.\u00a0 Hormones are classified into 5 main categories based on molecular structure:\r\n