BloodOutline

[Audio] © BIOLOGY 2060 lecture NotES – anatomy & PHYSIOLOGY II (A. IMHOLTZ) BLOOD P1 OF 4 1. Blood a Fluid connective tissue i Consists of cells suspended in a liquid fibrous matrix. ii. Blood cells = formed elements iii. Liquid matrix = plasma. b Formed elements consist of erythrocytes (red blood cells) leukocytes (white blood cells) and platelets. 2. Centrifuged blood divides into 3 portions a Plasma b Packed R-B-Cs (42-52% in ♂ and 37-47% in ♀. This % = hematocrit.) c Buffy layer containing W-B-Cs and platelets. (<1%) 3. Physical characteristics a Color ranges from scarlet (oxygen-rich) to dark red (oxygen poor). b Viscosity is 5x that of water due primarily to the presence of formed elements. c pH normally ranges from 7.35-7.45 (slightly alkaline). d Temperature is typically 100 degrees farenheit. e Volume is 4-5 liters for females and 5-6 liters for males. 4. Distribution functions a Carries O2 (from lungs) and nutrients (from GI tract and body stores) to all cells b Carries wastes from all cells to elimination sites (lungs for CO2; kidneys for nitrogenous wastes c Carries hormones (chemical signals) from endocrine organs to target tissues. 5. Regulatory functions a Regulates body T° by absorbing and distributing heat b Maintains body fluid pH by virtue of its many buffers c Maintains adequate body fluid volumes. 6. Protective functions a Prevents blood loss by initiating clotting mechanisms in response to blood vessel damage b Prevents infection via W-B-Cs and plasma immune proteins. 7. Blood plasma a 48-58% of blood volume in ♂ and 53-63% of blood volume in ♀. b 90% water. Water acts as a solvent and suspending medium. c Solutes dissolved in plasma include: plasma proteins nutrients electrolytes respiratory gases hormones and wastes. d Plasma proteins i Albumin = most abundant plasma protein 1. Produced by the liver 2. Maintains plasma osmotic pressure. 3. Acts as a buffer and is involved in the transport of steroids and bilirubin. ii. Globulins are another major type of plasma protein. 1. Many are produced in the liver and act as transport proteins for lipids metal ions and fat-soluble vitamins. 2. Other globulins known as antibodies are produced during the immune response. iii. Clotting proteins. 1. Most are produced in the liver for example prothrombin and fibrinogen. e Nutrients i Absorbed from the GI tract or body reserves and distributed throughout the body. ii. E.g. amino acids glucose fatty acids triglycerides vitamins and cholesterol. f Electrolytes (ions such as Ca2 plus Na plus and K plus et cetera) g Respiratory gases (dissolved C-O-2 O2 and N2) h Wastes (byproducts of cell metabolism for example urea uric acid ammonia creatinine and lactic acid).

[Audio] © BIOLOGY 2060 lecture NotES – anatomy & PHYSIOLOGY II (A. IMHOLTZ) BLOOD P2 OF 4 c Anucleate and lack organelles. d Stuffed with hemoglobin proteins. e 4-6 million R-B-Cs per L of blood. f Primary function is O2 transport. Play a minor role in C-O-2 transport. 9. Hemoglobin a Abundant within RBCs. Small amount is also dissolved in plasma. reversibly binds and releases O2. b Protein (globin) bound to red heme pigments. Globin consists of four polypeptide chains (2 alpha chains and 2 beta chains) each with their own heme. Each heme contains one Fe atom that can reversibly bind one O2 molecule. c Each can transport four O2 molecules. d In lungs Hb binds O2 and is oxyhemoglobin. e In tissues Hb releases O2 and is then deoxyhemoglobin or reduced hemoglobin. f 20% of blood's C-O-2 is transported by combining with Hb's amino acids. (Carbaminohemoglobin). 10. Hemopoiesis (or Hematopoiesis) = Blood cell formation. a Occurs in red bone marrow. Adult red marrow is found in ribs vertebrae sternum pelvis proximal humeri and proximal femurs. b All blood cells arise from a hemopoietic stem cell (hemocytoblast). 11. Erythropoiesis = R-B-C formation. a Hemocytoblast divides and differentiates. Its nucleus and organelles are discarded while Hb stores are built up to tremendous levels. b Requires iron and vitamin B12. 12. R-B-C levels a # of R-B-Cs in blood is remarkably constant and maintained via negative feedback. b Too few R-B-Cs compromises O2 transport. Too many causes a detrimental  in blood viscosity. c The hormone erythropoietin (E-P-O--) controls the rate of erythropoiesis. d The kidneys always release EPO. e If blood O2 content  the kidneys  E-P-O release which stimulates R-B-C synthesis to. f O2 delivery to the kidney could change due to R-B-C count altitude increased aerobic activity lung disease or CV disease. 13. R-B-C removal/recycling a After 120d R-B-Cs become old/damaged. The lack of a nucleus and organelles precludes replication or self-repair. b Old/damaged R-B-Cs are engulfed by scavenger cells known as macrophages in the spleen liver and red bone marrow. c Hb within the phagocytosed R-B-C will be broken down and partially recycled and partially excreted. d Hb is broken down into its globin and heme portions. e Globin is reduced to amino acids which are released from the macrophage into the blood stream for reuse elsewhere. f Iron is removed from heme and then transported to the liver by a plasma protein transferrin. In the liver iron is stored as ferritin or hemosiderin. g The remainder of the heme is converted into a pigment called bilirubin. Bilirubin is released from the macrophage and transported to the liver by albumin. The liver then modifies.

[Audio] © BIOLOGY 2060 lecture NotES – anatomy & PHYSIOLOGY II (A. IMHOLTZ) BLOOD P3 OF 4 g Perform diapedesis (in other words leave the blood stream) and enter connective or lymphatic tissue where they mount an immune response. h Capable of flowing thru the tissue spaces with an amoeboid-like motion. i Attracted to chemicals by pathogens damaged cells or activated W-B-C-s-. (Positive chemotaxis.) j 5 types: neutrophils lymphocytes monocytes eosinophils and basophils. k "Never let monkeys eat bananas" specifies the 5 types in order of abundance. l Divided into 2 large classes: granulocytes and agranulocytes. m Granulocytes contain membrane-bound granules that are dyed by Wright's stain. n Agranulocytes lack stainable granules. o Granulocytes include neutrophils eosinophils and basophils. All are spherical larger than R-B-C-s have lobed nuclei and stain specifically with Wright's stain. p Agranulocytes include lymphocytes and monocytes. 15. Neutrophils a Most numerous circulating WBC. b Constitute 50-70% of circulating W-B-C population. c Contain fine lilac colored granules that take up acidic and basic dyes d Nucleus consist of 3-6 lobes ( Polymorphonuclear). e Count increases during acute bacterial infections. 16. Eosinophils a Make up 2-4% of the circ. W-B-C pop. b Bilobed nuclei. c Take up acidic dyes which cause their granules to turn reddish orange. d Attack parasitic worms. e Engulf immune complexes involved in allergic rxns. (Lessening their severity.) 17. Basophils a Make up <1% of the circ. W-B-C pop. b Take up basic dyes which cause their granules to turn a dark purple. Granules contain a vasodilator (histamine) and an anticoagulant (heparin). Released during inflammation. 18. Lymphocytes a Comprise 30% of the circ. W-B-C pop. b Large round purple nuclei taking up most of the cell volume. c Trillions of lymphocytes in the body but only a relatively small # in the blood. Most are found w/i lymphatic tissues (for example lymph nodes spleen). d 2 main types i T lymphocytes defend against virus-infected and tumor cells and control and manage the immune response. ii. B lymphocytes differentiate into plasma cells which produce antibodies. 19. Monocytes a Comprise 3-8% of the circ. W-B-C pop. b Largest leukocyte – up to 3x the size of an RBC. c Pale blue cytoplasm and a dark U or kidney-shaped nucleus. d Leave the bloodstream to become macrophages – cells specialized in phagocytosis of foreign particles and debris. 20. Leukopoiesis = W-B-C formation a Occurs primarily within the red marrow but also w/i lymphatic tissues. b Stem cell for all W-B-Cs is the hemocytoblast. 21. Platelets a Fragments (2-4 m diam.) of extremely large bone marrow cells (megakaryocytes) that are derived from hemocytoblasts. b Contain membrane-bound granules filled with chemicals involved in blood clotting. c Help form.

[Audio] © BIOLOGY 2060 lecture NotES – anatomy & PHYSIOLOGY II (A. IMHOLTZ) BLOOD P4 OF 4 b Consists of 3 events: vascular spasm platelet plug formation and coagulation. 23. Vascular spasm a Damaged vessels release chemicals that cause the smooth muscle in their walls to contract. This  vessel diameter which will  blood loss and  local BP (thus facilitating patching and repair). 24. Platelet plug formation a Platelets are activated when the tearing of a blood vessel wall exposes the collagen that underlies the vessel's endothelium (in other words its simple squamous epithelial lining). b Activated platelets then aggregate at the injury site. c Aggregated activated platelets release chemicals that: enhance vascular spasm; are involved in coagulation; and facilitate the activation and aggregation of more platelets at the injury site (a plus feedback process). d Aggregation of platelets is a platelet plug and is a temporary seal to the break in the vessel wall. e Platelet plug is restricted to the injury site b/c intact endothelial cells release the chemical prostacyclin which inhibits platelet aggregation. 25. Procoagulants against anticoagulants a Procoagulants initiate and stimulate the formation of a blood clot b Anticoagulants inhibit and impede the formation of a blood clot. c When vessels are intact the anticoagulants "win" and clotting does not occur. However blood vessel damage sets off a chain of events whereby the procoagulants dominate and coagulation occurs. 26. Coagulation a Complicated multi-step process that results in the formation of a sturdy clot that seals the tear until repairs are complete. b In response to vessel damage prothrombin activator (P-T-A--) is formed. c P-T-A converts the inactive plasma protein prothrombin into the active thrombin. d Thrombin converts the insoluble plasma protein fibrinogen into the insoluble fibrin. e Fibrin molecules then link to one another and form a meshwork of strands on the platelet plug. R-B-C-s W-B-C-s and plasma are trapped w/i the fibrin mesh. This is a blood clot. f 2 pathways by which P-T-A is formed: extrinsic and intrinsic. g Extrinsic path i Begins when blood is exposed to a chemical released by damaged tissue cells outside the blood vessel. ii. Has few steps and thus P-T-A can be formed quickly. h Intrinsic path i Begins in response to the release of certain chemicals by damaged blood vessel cells. ii. Has many steps which makes it slower but allows for amplification which yields tremendous amounts of PTA. i In the body both pathways typically occur in response to the same event. Having 2 pathways allows for P-T-A to be formed quickly (extrinsic) as well as in large amounts (intrinsic). j Multiple clotting factors are involved in the coagulation process. Many of these are formed in the liver. Vitamin K is required for their synthesis. Calcium is also required for coagulation..