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The circulatory system: Blood

The circulatory system: Blood. Chapter 18 BSC 1086C Fall 2007. Functions of Circulatory System. _____________ O2, CO2, nutrients, wastes, hormones, and heat _____________ WBCs, antibodies, (immune system to fight infection) and platelets (blood clotting to prevent blood loss)

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The circulatory system: Blood

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  1. The circulatory system:Blood Chapter 18 BSC 1086C Fall 2007

  2. Functions of Circulatory System • _____________ • O2, CO2, nutrients, wastes, hormones, and heat • _____________ • WBCs, antibodies, (immune system to fight infection) and platelets (blood clotting to prevent blood loss) • _____________ • fluid regulation (water distribution) and buffering (pH levels of body fluids)

  3. Blood • Adults have 4-6 L of blood (~1.5 gallons) • ___________: a clear extracellular fluid • ___________: blood cells and platelets • Centrifuge blood to separate components 18.2 18.1

  4. Plasma and Plasma Proteins • Plasma – non-living fluid matrix • consists of water (92%), ions (electrolytes) and proteins • 3 major categories of plasma proteins • _____________ - most abundant. • solute transport and pH buffering • _____________ (antibodies) • solute transport and immunity • alpha, beta, and gamma globulins • _____________ • precursor of fibrin threads that help form blood clots • Plasma proteins formed by ___________ • except globulins (produced by plasma cells)

  5. Nonprotein Components of Plasma • ________________ • amino acids (from diet and tissue breakdown) • nitrogenous wastes (urea) • toxic end products of catabolism • normally removed by the kidneys • ________________ • glucose, vitamins, fats, minerals, etc • ________ and ___________ • ________________ • Na+ makes up 90% of plasma cations

  6. Formed elements in blood • __________________ • Most abundant formed element • 200 billion made per day • no cell nucleus (and few other organelles) • blood type determined by surface glycoprotein and glycolipids • Function • 1) • 2) • Biconcave shape. Why??

  7. RBCs and Gas Transport • RBCs are packed full of ______________ (280 million/cell) • O2 binds to non-protein ____________(Fe2+ an ionic form of iron) • each heme group binds to 1 O2, therefore 1 RBC can carry approximately 1 billion molecules of O2! 18.5

  8. RBCs and Gas Transport • RBCs also contain the enzyme carbonic anhydrase • This enzyme catalyzes the reaction of CO2 with H2O This serves 2 functions:

  9. Erythrocytes and Hemoglobin • RBC count and hemoglobin concentration indicate amount of O2 blood can carry • hematocrit (packed cell volume) - __________________ • men 42- 52% cells; women 37- 48% cells • hemoglobin concentration of whole blood • men 13-18g/dL; women 12-16g/dL • RBC count • men 4.6-6.2 million/L; women 4-2-5.4 million/L • Values are lower in women…..why? • 1) • 2)

  10. Leave bone marrow and enter blood stream Stem cells that form ALL formed elements in blood Location: EPO:________________ A hormone that stimulates ECFU to transform into an erythroblast RBC production: Erythropoiesis Fig 18.6 Erythroblasts multiply and synthesize hemoglobin RBC production rate ~ 2.5 million / second

  11. Erythrocyte Homeostasis • Negative feedback control • drop in RBC count causes _______________________ • EPO production stimulates bone marrow • RBC count  in 3 - 4 days • Stimulus for erythropoiesis • low levels O2 • increase in exercise • loss of lung tissue in emphysema 18.7

  12. Bile pigments Erythrocytes Recycle/Disposal • RBCs lyse in narrow channels in ____________ • Macrophages in _________ • digest membrane bits • separate heme from globin • Globins converted to AAs • iron removed from hemeand recycled 18.9

  13. Blood typing: Antigens and Antibodies • ___________ • unique molecules on cell surface • used to distinguish self from foreign • foreign antigensgenerate immune response • ___________ • secreted by plasma cells • as part of immune response to foreign matter • ___________ • antibody molecule binding to antigens • causes clumping

  14. Blood Types • RBC antigens • agglutinogens; A and B • on RBC surface • Your ABO blood type is determined by presence or absence of antigens (agglutinogens) on RBCs • type A person has ____ antigens • type B person has ____ antigens • type AB has ________ antigens • type O has __________ antigen • most common - type O • rarest - type AB 18.12

  15. Plasma antibodies • Antibodies (agglutinins); anti-A and -B • Appear 2-8 months after birth; at maximum concentration at 10 yr. • Anti -A and/or -B (both or none) are in plasma • you do not form antibodies against your antigens • Therefore: • type A blood has _____________ antibodies • type B blood has _____________ antibodies • type O blood has _____________ antibodies • type AB blood has _____________antibodies • Transfusion with wrong blood type = agglutination

  16. Rh Group • Rh (D) agglutinogens discovered in rhesus monkey in 1940 • Rh+ blood type has D agglutinogens on RBCs • Rh frequencies vary among ethnic groups • Anti-D agglutinins not normally present

  17. Leukocytes (WBCs) • 5,000 to 10,000 WBCs/L • Conspicuous nucleus • Travel in blood before migrating to connective tissue • Function:_____________________

  18. Granulocytes • - in bacterial infections • -phagocytosis of bacteria • -release antimicrobial • chemicals • in parasitic infections -phagocytosis of antigen- antibody complexes, allergens and inflammatory chemicals • -release enzymes to destroy • parasites •  in chicken pox, sinusitis, diabetes • -secrete • histamine • (vasodilator) • -secrete heparin • (anticoagulant)

  19. Agranulocytes •  in diverse infections and immune responses • -destroy cells (cancer, foreign, and virally infected cells) • -“present” antigens to activate other immune cells • -coordinate actions of other immune cells • -secrete antibodies and provide immune memory • in viral infections and inflammation • -differentiate into macrophages • -phagocytize pathogens and debris • -“present” antigens to activate other immune cells

  20. Platelets 18.20 • Small fragments of _____________ cytoplasm • 2-4 m diameter; contain “granules” • amoeboid movement and phagocytosis • Normal Count - 130,000 to 400,000 platelets/L • Functions • 1 • 2 • 3 • 4

  21. Hemostasis: preventing blood loss • Causes • 1 • 2 • 3 • Effects • prompt constriction of a broken vessel • pain receptors - short duration (minutes) • smooth muscle injury - longer duration • provides time for other two clotting pathways 18.21 1) Vascular spasm

  22. Hemostasis: preventing blood loss • broken vessel exposes _____________ • platelet pseudopods stick to damaged vessel and other platelets - draw walls of vessel together forming a __________ • Release 5-HT (vasoconstictor), ADP, and thromboxane A2 • positive feedback cycle is active until break in vessel is sealed 18.21 2) Platelet plug formation

  23. Hemostasis: preventing blood loss • Clotting - most effective defense against bleeding • conversion of plasma protein __________ into insoluble _________ threads to form framework of clot • Extrinsic and intrinsic pathways converge on common reaction cascade to produce fibrin 3) Coagulation 18.21

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