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Blood

Blood. Ch 19. Blood. Artery. White blood cells. Platelets. Red blood cells. Function Blood. Deliver O2 Remove metabolic wastes Maintain temperature, pH, and fluid volume Protection from blood loss- platelets Prevent infection- antibodies and WBC Transport hormones. Blood.

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Blood

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  1. Blood Ch 19

  2. Blood Artery White blood cells Platelets Red blood cells

  3. Function Blood • Deliver O2 • Remove metabolic wastes • Maintain temperature, pH, and fluid volume • Protection from blood loss- platelets • Prevent infection- antibodies and WBC • Transport hormones

  4. Blood Plasma-55% Buffy coat-<1% Formed elements-45%

  5. Blood Plasma Components-55% 90% Water 8% Solutes: • Proteins Albumin (60 %) Alpha and Beta Globulins Gamma Globulins fibrinogens • Gas • Electrolytes

  6. Blood Plasma Components • Organic Nutrients Carbohydrates Amino Acids Lipids Vitamins • Hormones • Metabolic waste CO2 Urea

  7. Buffy Coat- <1% • Leukocytes • Platelets

  8. Formed Elements of the Blood-45% • Erythrocytes (red blood cells) • Leukocytes (white blood cells) • Platelets (thrombocytes)

  9. Erythrocytes

  10. Erythrocyte7.5m in dia ·Anucleate- so can't reproduce; however, repro in red bone marrow ·Hematopoiesis- production of RBC ·Function- transport respiratory gases ·Hemoglobin- quaternary structure, 2  chains and 2  chains ·Lack mitochondria. Why? ·1 RBC contains 280 million hemoglobin molecules ·Men- 5 million cells/mm3 ·Women- 4.5 million cells/mm3 ·Life span 100-120 days and then destroyed in spleen (RBC graveyard)

  11. Hemoglobin

  12. Hematopoiesis • Hematopoiesis (hemopoiesis): blood cell formation • Occurs in red bone marrow of axial skeleton, girdles and proximal epiphyses of humerus and femur

  13. Hematopoiesis • Hemocytoblasts (hematopoietic stem cells) • Give rise to all formed elements • Hormones and growth factors push the cell toward a specific pathway of blood cell development • New blood cells enter blood sinusoids

  14. Erythropoiesis • Erythropoiesis: red blood cell production • A hemocytoblast is transformed into a proerythroblast • Proerythroblasts develop into early erythroblasts

  15. Erythropoiesis • Phases in development • Ribosome synthesis • Hemoglobin accumulation • Ejection of the nucleus and formation of reticulocytes • Reticulocytes then become mature erythrocytes

  16. Stem cell Committed cell Developmental pathway Phase 1 Ribosome synthesis Phase 2 Hemoglobin accumulation Phase 3 Ejection of nucleus Reticulo- cyte Erythro- cyte Proerythro- blast Early erythroblast Late erythroblast Normoblast Hemocytoblast Figure 17.5

  17. Regulation of Erythropoiesis • Too few RBCs leads to tissue hypoxia • Too many RBCs increases blood viscosity • Balance between RBC production and destruction depends on • Hormonal controls • Adequate supplies of iron, amino acids, and B vitamins

  18. Hormonal Control of Erythropoiesis • Erythropoietin (EPO) • Direct stimulus for erythropoiesis • Released by the kidneys in response to hypoxia

  19. Hormonal Control of Erythropoiesis • Causes of hypoxia • Hemorrhage or increased RBC destruction reduces RBC numbers • Insufficient hemoglobin (e.g., iron deficiency) • Reduced availability of O2 (e.g., high altitudes)

  20. Hormonal Control of Erythropoiesis • Effects of EPO • More rapid maturation of committed bone marrow cells • Increased circulating reticulocyte count in 1–2 days • Testosterone also enhances EPO production, resulting in higher RBC counts in males

  21. Formation & Destruction of RBCs

  22. RBC Diseases Anemia- when blood has low O2 carrying capacity; insufficient RBC or iron deficiency. Factors that can cause anemia- exercise, B12 deficiency Polycythemia- excess of erythrocytes,  viscosity of blood; 8-11 million cells/mm3 Usually caused by cancer, tissue hypoxia, dehydration; however, naturally occurs at high elevations Blood doping- in athletesremove blood 2 days before event and then replace it; Epoetin;- banned by Olympics.

  23. RBC Diseases Sickle-cell anemia- HbS results from a change in just one of the 287 amino acids in the  chain in the globin molecule. Found in 1 out of 400 African Americans. Abnormal hemoglobin crystalizes when O2 content of blood is low, causing RBCs to become sickle-shaped. Homozygous for sickle-cell is deadly, but in malaria infested countries, the heterozygous condition is beneficial.

  24. Genetics of Sickle Cell Anemia Genetics of Sickle Cell Anemia

  25. Types of Leukocytes 4,000-11,000 cells/mm 3 Never let monkeys eat bananas Granulocytes Neutrophils- 40-70% Eosinophils- 1-4% Basophils- <1% Agranulocytes Monocytes- 4-8% Lymphocytes- 20-45%

  26. Lymphocyte Eosinophil Basophil platelet Neutrophil Monocyte

  27. eosinophil neutrophil monocyte RBC neutrophil monocyte lymphocyte lymphocyte basophil

  28. ID WBC’s

  29. Diapedesis Leukocyte Squeezing Through Capillary Wall

  30. WBC Diseases • Leukopenia • Abnormally low WBC count—drug induced • Leukemias • Cancerous conditions involving WBCs • Named according to the abnormal WBC clone involved • Mononucleosis • highly contagious viral disease caused by Epstein-Barr virus; excessive # of agranulocytes; fatigue, sore throat, recover in a few weeks

  31. Platelets • Small fragments of megakaryocytes • Formation is regulated by thrombopoietin • Blue-staining outer region, purple granules • Granules contain serotonin, Ca2+, enzymes, ADP, and platelet-derived growth factor (PDGF)

  32. Stem cell Developmental pathway Hemocyto- blast Promegakaryocyte Megakaryoblast Megakaryocyte Platelets Figure 17.12

  33. Platelet Plug Clotting Factors Hemostasis- stoppage of bleeding Platelets: 250,000-500,000 cells/mm3 Tissue Damage

  34. Hemostasis: • Vessel injury 2. Vascular spasm 3. Platelet plug formation 4. Coagulation

  35. Clotting Factors thromboplastin Prothrombin Thrombin Fibrinogen Fibrin Hemostasis(+ feedback) Traps RBC & platelets Platelets release thromboplastin

  36. Blood Clot RBC Platelet Fibrin thread

  37. Disorders of Hemostasis • Thromboembolytic disorders: undesirable clot formation • Bleeding disorders: abnormalities that prevent normal clot formation

  38. Thromboembolytic Conditions • Thrombus: clot that develops and persists in an unbroken blood vessel • May block circulation, leading to tissue death • Embolus: a thrombus freely floating in the blood stream • Pulmonary emboli impair the ability of the body to obtain oxygen • Cerebral emboli can cause strokes

  39. Thromboembolytic Conditions • Prevented by • Aspirin • Antiprostaglandin that inhibits thromboxane A2 • Heparin • Anticoagulant used clinically for pre- and postoperative cardiac care • Warfarin • Used for those prone to atrial fibrillation

  40. Bleeding Disorders • Thrombocytosis- too many platelets due to inflammation, infection or cancer • Thrombocytopenia- too few platelets • causes spontaneous bleeding • due to suppression or destruction of bone marrow (e.g., malignancy, radiation) • Platelet count <50,000/mm3 is diagnostic • Treated with transfusion of concentrated platelets

  41. Bleeding Disorders • Impaired liver function • Inability to synthesize procoagulants • Causes include vitamin K deficiency, hepatitis, and cirrhosis • Liver disease can also prevent the liver from producing bile, impairing fat and vitamin K absorption

  42. Bleeding Disorders • Hemophilias include several similar hereditary bleeding disorders • Symptoms include prolonged bleeding, especially into joint cavities • Treated with plasma transfusions and injection of missing factors

  43. Hemophiliac- a sex-linked recessive trait, primarily carried by males (x chromosome)

  44. Blood Types Type A Type B Type AB Type O

  45. Blood Typing Blood type is based on the presence of 2 major antigens in RBC membranes-- A and B Blood type Antigen Antibody A A anti-B B B anti-A A & B AB no anti body Neither A or B O anti-A and anti-B Antigen- protein on the surface of a RBC membrane Antibody- proteins made by lymphocytes in plasma which are made in response to the presence of antigens. They attack foreign antigens, which result in clumping (agglutination)

  46. ABO Blood Types Type A b b Produces anti-B antibodies b b b b b b

  47. ABO Blood Types Type B a a a Produces anti-A antibodies a a a a a a a

  48. ABO Blood Types Type AB Produces neither anti-A nor anti-B antibodies

  49. ABO Blood Types Type O b a b a a Produces both anti-A and anti-B antibodies b a b a a b a b a a a b b

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