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Hemo, hemato refers to blood

Hemo, hemato refers to blood. Characteristics of Blood. Fluid; connective tissue Living cells = formed elements Non-living matrix = plasma Transport - Gases, nutrients, wastes, hormones, heat Regulation Defense. Blood Plasma. about 90 percent water Includes dissolved substances:

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Hemo, hemato refers to blood

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  1. Hemo, hemato refers to blood

  2. Characteristics of Blood • Fluid; connective tissue • Living cells = formed elements • Non-living matrix = plasma Transport - Gases, nutrients, wastes, hormones, heat Regulation Defense

  3. Blood Plasma • about 90 percent water • Includes dissolved substances: • Nutrients • Salts (metal ions) • Respiratory gases • Hormones • Proteins • Waste products

  4. Formed Elements • Erythrocytes = red blood cells, RBC • Leukocytes = white blood cells, WBC • Platelets = cell fragments

  5. Erythrocytes (Red Blood Cells) • Carry oxygen • Biconcave disks • Essentially bags of hemoglobin • Anucleate (no nucleus) • Contain very few organelles • Outnumber white blood cells 1000:1 • Hematocrit - % RBC

  6. Fate of Erythrocytes • Unable to divide, grow, or synthesize proteins • Wear out in 100 to 120 days • then eliminated by phagocytes in spleen or liver • RBCs replaced by dividing stem cells

  7. Control of Erythrocyte Production • Homeostasis triggered by blood oxygen levels • Kidneys produce erythropoietin as a response to reduced oxygen levels in the blood

  8. Hematopoiesis In red bone marrow RBCs, WBCs

  9. Leukocytes (White Blood Cells) • Body’s defense against disease • Has nucleus and organelles • moves into and out of blood vessels (diapedesis) • moves by amoeboid motion • responds to chemicals from damaged tissues

  10. Granulocytes 2. Eosinophils - Large brick-red cytoplasmic granules • Found in response to allergies and parasitic worms 3. Basophils - Have histamine-containing granules • Initiate inflammation 1. Neutrophils • Multilobed nucleus with fine granules • Act as phagocytes at active sites of infection

  11. Agranulocytes • Lymphocytes (B, T cells) • Large nucleus • Specific immune response • Monocytes • Largest of the white blood cells • Function as macrophages • Important in fighting chronic infection

  12. leukemia

  13. Platelets • Derived from ruptured multinucleate cells (megakaryocytes) • Needed for the clotting process • Normal platelet count = 300,000/mm3

  14. Hemostasis • = Stoppage of blood flow • Result of a break in a blood vessel • Fast reaction - 3-6 minutes • 3 phases

  15. 1. Vascular Spasms • spasm by blood vessel muscles • blood vessel narrows, decreasing blood loss

  16. 2. Platelet Plug Formation • Collagen fibers exposed • Platelets become “sticky” and cling to fibers • release chemicals to attract more platelets • Platelets form a plug

  17. 3. Coagulation • a clotting cascade • Injured tissues stimulate release of prothrombin activator • Which (with Ca++) converts prothrombin to thrombin (an enzyme) • Thrombin joins fibrinogen proteins into hair-like fibrin. Network that traps cells. • Process also involves vitamin K, other blood protein clotting factors, thromboplastin

  18. Coagulation • Fibrin forms a meshwork (the basis for a clot)

  19. Undesirable Clotting • Thrombus • A clot in an unbroken blood vessel • Embolus • A thrombus that breaks away and floats freely in the bloodstream Bleeding Disorders • Hemophilia, thrombocytopenia

  20. Blood Groups and Transfusions • Large losses of blood: consequences • Loss of 15 to 30 percent causes weakness • Loss of over 30 percent causes shock, which can be fatal • Transfusions to replace blood quickly • must be same blood group

  21. Blood contains genetically determined proteins • A foreign protein (antigen) may be attacked by the immune system

  22. Blood is “typed” by using antibodies that will cause blood cells to clump (agglutination)

  23. Blood Typing Figure 10.8

  24. Rh Blood Groups • Named for one of eight Rh antigens (agglutinogen D) • Most Americans are Rh+ • Problems can occur in mixing Rh+ blood into a body with Rh– blood

  25. Danger is only when the mother is Rh– and the father is Rh+, and the child inherits the Rh+ factor

  26. Developmental Aspects of Blood • Sites of blood cell formation • fetal liver, spleen are early sites of blood cell formation • Bone marrow takes over hematopoiesis by the seventh month • Fetal hemoglobin differs from hemoglobin produced after birth

  27. Blood Disorders • Carbon monoxide poisoning • Anemia - reduced oxygen capacity • Leukemia - excess WBC • Mononucleosis - viral infection • Blood poisoning

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