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Chapter 12 Blood Composition of Plasma 2 Components of Whole Blood: Hematocrit Figure 17.1, Marieb, 6th ed. Withdraw blood and place in tube 1 2 Centrifuge Plasma (55% of whole blood) Formed elements Buffy coat: leukocyctes and platelets (<1% of whole blood) Erythrocytes (45% of whole blood) Before centrifugation After centrifugation Fig. 12-1 3 Composition of Whole Blood Fig. 12-1 4 Blood O2 Content in Each Type of Blood Vessel Fig. 12-2 5 >Erythrocytes >Leukocytes >Platelets (Thrombocytes) 6 Blood Cells Preparing a Blood Smear Fig. 12-3 7 Figure 13-1 Shifting Locations of Hemopoiesis during Development and Aging 9 Hematopoeisis: Erythrocytes and Leukocytes Fig. 13-9 10 Fig. 13-6 Erythropoeisis Mitosis occurs in these stages No mitosis occurs in these stages Erythropoietin Mechanisms for Regulating Erythropoiesis Fig. 17-6. Marieb, 6th ed. 12 Life Cycle of Red Blood Cells 13 Fig. 17.7 Normal Human Erythrocytes Fig. 12-4 14 Erythrocytes Fig. 12-3 Biconcave discs, anucleated-- almost no organelles Filled with hemoglobin (Hb), a protein that transports O2 and CO2 Contain the plasma membrane protein spectrin and other proteins that: --Give flexibility to erythrocytes --Allow them to change shape Female: 3.9-5.5 X 106/µL Male: 4.1-6 X 106/µL Reticulocytes: 1% of erythrocytes 15 Spectrin Meshwork Beneath Plasma Membrane of RBC Spectrin meshwork strengthens and maintains the shape of red blood cells. 16 Blood Typing of ABO Blood Types Fig. 17-15, Marieb, 6th ed. 17 Universal donor Universal recipient Sickle Cell Fig. 12-5 18 Anemias: Erythrocyte Disorders Anemias occur when hemoglobin levels are lower than normal, reducing O2-carrying capacity. There are 3 major categories of anemias: 1) Too few erythrocytes: hemorrhagic, hemolytic, aplastic 2) Normal number of erythrocytes, but they do not contain normal amounts of hemoglobin: iron- deficiency, pernicious anemia 3) Abnormal hemoglobin: sickle-cell, thalassemias (abnormal or missing chains) 19 >Erythrocytes >Leukocytes >Platelets 20 Blood Cells Leukocytes (WBCs) Leukocytes are complete cells: Are far less numerous (1 x 10-3) than RBCs Make up <1% of the total blood volume Can leave capillaries via diapedesis Move through tissue spaces 21 Five Types of Human Leukocytes Fig. 12-6 22 Fig. 12-6 Leukocytes in Postcapillary Venule at Sites of Inflammation Macrophage releases proinflammatory cytokines; in response, endothelium synthesizes selectins (New expression) Leukocytes (White Blood Cells) _______________________________________________ Cell Type #/µL % Neutrophil 5,000 60-70 Eosinophil 150 2-4 Basophil 30 0.5 Lymphocyte 2,400 28 Monocyte 350 5 (Erythrocyte 4-6,000,000) ____________________________________ Total 6,000-10,000 24 Neutrophils Fig. 12-7 25 Eosinophils Fig. 12-9 26 Basophils Fig. 12-10 27 Basophil (Granulocyte) Fig. 12-12 Account for 0.5% of WBCs and: Have U- or S-shaped nuclei with two or three conspicuous constrictions Are functionally similar to mast cells Have large, purplish-black (basophilic) granules that contain histamine Histamine – inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect) 28 Lymphocytes Fig. 12-11 29 Lymphocyte (Agranulocytes) Fig. 12-15 Account for 25% of WBCs (leukocytes) Localized mostly in lymphoid tissue; some circulate in the blood Three types: T cells, B cells, and natural killer (NK) cells --T cells function in the immune response --B cells transform into plasma cells; plasma cells produce antibodies --NK cells kill infected cells Large, dark-purple, circular nuclei with a thin rim of blue cytoplasm 30 Monocytes (Agranulocyte) Fig. 12-12 31 Monocyte (Agranulocyte) Fig. 12-17 Pale-blue cytoplasm Purple-staining, U- or kidney-shaped nucleus Transform into macrophages Are highly mobile and actively phagocytic Activate lymphocytes to mount an immune response 32 Blood Cells >Erythrocytes >Leukocytes >Platelets 33 Composition of Plasma Genesis of Platelets 34 Fig. 17-12. Marieb, 6th ed. 60 µm Platelets are responsible for initiating blood clotting. Small fragments break off from giant megakaryocytes that reside in bone marrow. 300,000/µL Platelets recognize collagen fibers in broken blood vessels. Platelets form a plug and then other blood factors form a fibrin mesh around that plug. Fig. 13-5 Sinusoidal Endothelium in Active Marrow Platelets Fig. 12-13 36 C = collagen EP = endothelial cell processes = swollen degranulated platelets Fibrin Clot Fig. 12-14 37
