Blood

1. Blood

2. Blood Characteristics Stats: Connectivetissue Volume : 4-6L pH: 7.35-7.45 Temp: 38oC or 100.4 oF Components: Plasma – 55% Erythrocytes – 45% Leukocytes/Platelets - <1% Functions: Transport – of hormone, gases, nutrients, etc Regulation – of pH, body temp, water balance Protection – from blood loss and infection Figure 17.1

3. Plasma • Plasma – the liquid component of blood • Components: • Water – 90% of volume • Plasma proteins – 8% of volume • Most produced by liver • Albumin – most abundant protein (60%), a transport protein • Globulins (36%) – transport proteins and antibodies • Fibrinogen (4%) – clotting protein • Nonprotein solutes • Nitrogenous wastes • Electrolytes • Respiratory gases • Hormones Table 17.1

4. Formed Elements FormedElements – the cellular components of blood Erythrocytes- red blood cells Leukocytes – white blood cells Thrombocytes - platelets Figure 17.2

5. Erythrocytes • Erythrocytes – red blood cells • Number – 5M/ µL • Diameter: 7.5 µm • Shape – biconcave, increases SA • Anucleate – lack a nucleus at maturity • Functions – oxygen and carbon dioxide transport Figure 17.3

6. Hemoglobin • Hemoglobin (Hb) - Protein composing 97% of RBC volume • Globin – amino acid-based portion with 2 alpha chains,2 beta chains • Heme – pigment portion with a central Iron atom. 4, one per globin chain • 4 heme = 4 oxygen x 250M Hb/RBC = 1B oxygen/RBC! • Variations – oxyhemoglobin, deoxyhemoglobin, carbaminohemoglobin Figure 17.4

7. Erythropoeisis Hematopoiesis – blood cell formation, occurs in red bone marrow Erythropoiesis – red blood cell production - all blood cells arise from a common stem cell, a hemocytoblast - after Hb accumulates, the nucleus and organelles beak down - Now reticulocytes, they enter the bloodstream and become mature RBC’s Erythropoietin (EPO) – hormone that triggers RBC production Figure 17.5

8. Regulating Erythropoesis Low blood oxygen levels triggers erythropoietin (EPO) release from the kidneys EPO causes activity of red bone marrow RBC count rises Blood oxygen levels rise, inhibiting EPO release RawMaterials – amino acids, lipids, carbohydrates, Iron, and vitamin B Figure 17.6

9. Erythrocyte Breakdown • Lifespan – circulate for 100 - 120 days • Breakdown – RBC’s engulfed by macrophages in liver, spleen, and bone marrow • Hemoglobin breakdown • Hemoglobin is split into heme and globin • Globin’s amino acids are recycled to the blood • Heme’s iron is stored in the liver for future use • Heme’s pigment, now bilirubin, is used in bile production Figure 17.7

10. Erythrocyte Disorders Anemia – any condition leading to a lowered oxygen carrying capacity of the blood - Hemorrhagic anemia – due to blood loss - Hemolytic anemia – due to RBC rupture - Iron-deficiency anemia – unable to build RBC’s - Sickle-cell anemia – a genetic mutation leading to malformed Hb Polycythemia – an abnormally high RBC count, 6+ M cells/µL, resulting from bone marrow cancer or high elevations Figure 17.8

11. Leukocytes • Leukocytes – white blood cells • Number: 5,000-10,000 cells/µL • Possess nuclei and organelles • Function – immune responses • Diapedesis – ability of WBC’s to exit capillaries and enter tissues • Leukocytosis – WBC count > 11,000 cells/µL, a sign of infection Remembering WBC count: Never Let Monkeys Eat Bananas Figure 17.9

12. Leukocytes Granulocytes – WBC’s with cytoplasmic granules - Neutrophils, Eosinophils, and Basophils Agranulocytes – WBC’s without granules - Lymphocytes and Monocytes Figure 17.10

13. Neutrophils • Neutrophils: • Most abundant leukocyte, 50-70% of WBC’s, count rises during bacterial infection • Function – phagocytes of bacteria, fungi, etc. • ‘First responders’ to a site of inflammation • Multilobed nucleus • Granules contain enzymes and antimicrobial proteins Figure 17.10a

14. Eosinophils • Eosinophils: • 2-4% of WBC’s, count rises during parasitic infection • two-lobed nucleus • granules contain digestive enzymes specific to parasitic worms Figure 17.10b

15. Basophils • Basophils: • Rarest leukocyte, 0.5-1% of WBC’s • Granules contain histamine, an inflammatory chemical • Play a role in allergic reactions Figure 17.10c

16. Lymphocytes • Lymphocytes • 25-45 % of WBC’s • Large nucleus and little cytoplasm • Many located outside vessels, in lymph nodes, spleen, etc. • Two main types: • - T cells – target virally-infected cells • - B cells – make antibodies Figure 17.10d

17. Monocytes • Monocytes: • 3-8% of WBC’s • Largest WBC, 14-24 µm • Migrate into tissues where they become macrophages, long-lived phagocytes Figure 17.10e

18. Leukopoiesis • Leukopoiesis – the production of WBC’s • all arise from hemocytoblast stem cell • Lymphoid cell line produces only lymphocytes • Myeloid cell line produces all other WBC’s and RBC’s • Stimulated by inflammatory chemicals Figure 17.11

19. Platelets • Platelets: • Cytoplasmic fragments of marrow cells called megakaryocytes • Promote clotting by forming a temporary plug in a damaged vessel wall • Only circulate for 10 days, are constantly produced Figure 17.12

20. Hemostasis Hemostasis – the stoppage of bleeding Occurs in 3 steps: Vascular Spasm – constriction of the damaged vessel to limit blood loss Platelet plug formation – platelets stick to the exposed collagen fibers of a damaged blood vessel, become sticky, and chemically recruit more platelets to form a plug Coagulation – blood clotting, which occurs in three steps Figure 17.13a

21. Coagulation • Coagulation – a complex chemical process involving calcium and a balance of procoagulants and anticoagulants in 3 steps • Forming Prothrombin Activator – must form this enzyme to catalyze step 2 • Intrinsic pathway – slower, all components from within blood • Extrinsic pathway – faster, uses TF from damaged tissue • Thrombin formation – Prothrombin activator converts prothrombin to thrombin • Fibrin formation – Thrombin converts soluble fibrinogen into solid fibrin strands, which stick to form the clot Figure 17.13b

22. Hemostasis Clotretraction – the tightening of a clot within 30-60 minutes Fibrinolysis – the breakdown of a blood clot, performed by plasmin enzyme Anticoagulants – prevent overclotting by deactivating thrombin. Ex’s - Antithrombin III and Heparin Figure 17.14

23. Disorders of Hemostasis • Clotting Disorders: • Thrombus – a blood clot in an undamaged vessel • Embolus – a blood clot floating freely in the bloodstream • Embolism – a circulating blood clot that has blocked a vessel • Aspirin and Heparin are used to prevent and treat these clots • Bleeding Disorders: • Hemophilia – various hereditary conditions resulting in the lack of certain procoagulants • Thrombocytopenia – low platelet levels Figure 17.14

24. Blood Groups ABO blood groups – blood types according to proteins on the RBC cell surfaces Genes – A,B, and O genes encode for A, B, and O proteins . Every person possesses two of these genes Table 17.4

25. Blood Groups Agglutinogens – the proteins on the RBC surfaces Agglutinins – antibodies specific to the agglutinogens not possessed by an individual Agglutination – the clumping of cells that occur when agglutinins bind to their specific agglutinogens Table 17.4

26. Blood Groups • Blood Typing: • Split a blood sample into two halves • Mix one half with a serum of A agglutinins and the other with a serum of B agglutinins • Any sample that clumps (agglutinates) shows you that specific agglutinogen is present on the RBC surfaces Figure 17.15

27. Blood Groups

28. Blood Groups • Rh blood groups: • Classifies blood type as + or –, based on the presence or absence of an RBC surface protein • +,+ = a positive blood type • +, - = a positive blood type • -, - = a negative blood type • An Rh+ person can safely receive Rh- blood, but an Rh- person receiving Rh+ blood will cause agglutination…Why? • Erythroblastosis Fetalis – when an Rh- mother’s immune system rejects the Rh+ blood of her fetus. Does not happen if it her first pregnancy…Why?