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Blood

Blood. Chapter 12 Bio160. Blood Composition. Red blood cells. White blood cells. Platelets. Plasma. Red Blood Cells. Red blood cells ( Erythrocytes). Biconcave disks that contain oxygen-carrying hemoglobin.

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Blood

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  1. Blood Chapter 12 Bio160

  2. Blood Composition • Red blood cells • White blood cells • Platelets • Plasma

  3. Red Blood Cells • Red blood cells (Erythrocytes) Biconcave disks that contain oxygen-carrying hemoglobin When oxygen combines with hemoglobin bright red oxyhemoglobin results whereas deoxygenated blood (deoxyhemoglobin) is darker.

  4. Red Blood Cells Red blood cells discard their nuclei during development and so cannot reproduce or produce proteins. The number of red blood cells is a measure of the blood's oxygen-carrying capacity.

  5. Red Blood Cells • Red blood cell production In the embryo and fetus, red blood cell production occurs in the yolk sac, liver, and spleen; after birth, it occurs in the red bone marrow. The average life span of a red blood cell is 120 days.

  6. Red Blood Cells The total number of red blood cells remains relatively constant due to a negative feedback mechanism utilizing the hormone erythropoietin, which is released from the kidneys and liver in response to the detection of low oxygen levels.

  7. Red Blood Cells Vitamins B12, folic acid and iron are needed for red blood cell production A deficiency in red blood cells or quantity of hemoglobin results in anemia.

  8. Red Blood Cells • Red blood cell destruction With age, red blood cells become increasingly fragile and are damaged by passing through narrow capillaries. Macrophages in the liver and spleen phagocytize damaged red blood cells.

  9. Red Blood Cells Hemoglobin from the decomposed red blood cells is converted into heme and globin. Heme is decomposed into iron, which is stored or recycled, and biliverdin and bilirubin, which are excreted in bile.

  10. White Blood Cells • White blood cells (Leukocytes) Defend the body from disease. They are formed from hemocytoblasts. Leukocytes can squeeze between cells lining walls of blood vessels by diapedesis and attack bacteria and debris.

  11. White Blood Cells • Neutrophils Have red-staining fine cytoplasmic granules and a multilobed nucleus; they comprise 54-62% of leukocytes. They are phagocytic.

  12. White Blood Cells • Eosinophils Have coarse granules that stain deep red, a bilobed nucleus, and make up only 1-3% of circulating leukocytes. Eosinophils moderate allergic reactions as well as defend against parasitic infections.

  13. White Blood Cells • Basophils Have fewer granules that stain blue; they account for fewer than 1% of leukocytes. Basophils migrate to damaged tissues and release histamine to promote inflammation and heparin to inhibit blood clotting.

  14. White Blood Cells • Monocytes The largest blood cells, have variably shaped nuclei, and make up 3-9% of circulating leukocytes. They are phagocytic, engulfing large particles.

  15. White Blood Cells • Lymphocytes Long-lived, have a large, round nucleus, and account for 25-33% of circulating leukocytes. The major players in specific immune reactions and some produce antibodies.

  16. Platelets • Blood platelets Blood platelets are fragments of megakaryocytes. Platelets help repair damaged blood vessels by adhering to their broken edges.

  17. Blood Plasma • Blood Plasma Plasma is the clear, straw-colored fluid portion of the blood. • Plasma is mostly water but contains a variety of substances. • Plasma functions to transport nutrients and gases, regulate fluid and electrolyte balance, and maintain a favorable pH.

  18. Blood Plasma Plasma proteins • The albumins help maintain the osmotic pressure of the blood and account for 60% of the plasma proteins. • The globulins, comprising 36% of the plasma proteins, are designated as alpha, beta, and gamma globulins.

  19. Action Potentials Alpha and beta globulins function in transporting lipids and fat-soluble vitamins. Gamma globulins are a type of antibody. • Fibrinogen (4%) plays a primary role in blood coagulation.

  20. Blood Plasma Gases and nutrients • The most important blood gases are oxygen and carbon dioxide. • The plasma nutrients include amino acids, monosaccharides, nucleotides, and lipids.

  21. Blood Plasma Nonprotein Nitrogenous Substances • Nonprotein nitrogenous substances generally include amino acids, urea, and uric acid.

  22. Blood Plasma Plasma Electrolytes • They include sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and sulfate ions. • Some of these ions are important in maintaining osmotic pressure and pH of the plasma.

  23. Hemostasis • Hemostasis Hemostasis refers to the stoppage of bleeding. • Blood vessel spasm - muscles in vessel wall contract • Platelet plug formation - platelets stick to the exposed edges of damaged blood vessels, forming a net with spiny processes protruding from their membranes.

  24. Hemostasis • Blood coagulation – complex series of steps that leads to blood clot formation by conversion of fibrinogen into net-like fibrin, which catches blood cells before they can leave the body.

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