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Blood Chapter 17

Blood Chapter 17. Blood Composition and Characteristics. Major Components : Fig 17.1 Plasma Leukocytes Platelets   Erythrocytes Hematocrit = % RBC volume of total blood volume. Females have about 42%, males have about 47% (+/- 5%). Figure 17.1.

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Blood Chapter 17

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  1. BloodChapter 17

  2. Blood Composition and Characteristics • Major Components: Fig 17.1 • Plasma • Leukocytes • Platelets •   Erythrocytes • Hematocrit = % RBC volume of total blood volume. • Females have about 42%, males have about 47% (+/- 5%)

  3. Figure 17.1

  4. Blood Composition and Characteristics • Characteristics of Blood: • Denser, more viscous than water • Volume of blood: 4-5L (F), 5-6L (M). • Normal pH: 7.35 – 7.45

  5. Functions of Blood • Distribution • Delivery of O2 and other nutrients to all cells of the body • Transport of metabolic wastes to sites of elimination • Transport of hormones to target organs • Regulation • Maintaining body temperature • Maintaining pH of tissues via protein buffers and bicarbonate • Maintaining proper fluid volume in circulatory system and tissues • Protection • Preventing blood loss through hemostasis • Preventing infection via antibodies, complement, and WBCs

  6. Plasma Composition • Water 90% of plasma volume • Solutes 10% of plasma volume • ProteinsGlobulins- transport proteins (eg. albumin) and antibodies (immunoglobulins) • Clotting proteins (eg.fibrinogen) • Others: enzymes, hormones • Metabolic wastesurea, lactic acid, creatinine • Nutrientsglucose, amino acids, vitamins, lipids • Electrolytes Na+,K+,Ca2+, Cl-, P04-, bicarbonate • Respiratory GasesO2, CO2 ~8% ~2%

  7. Blood Cells/Formed Elements

  8. Erythrocytes-Red Blood Corpuscles • Characteristics: biconcave shape, ~7.5 mm diameter • 5 million/microliter • Function: respiratory gas tranpsort, via binding/unbinding to hemoglobin. (O2 and CO2) • Hemoglobin: protein globin + heme pigment • Contained within erythrocytes @ 12-20 g/100 ml blood • 4 globin subunits/Hb; each one has 1 heme that binds 1 O2 molecule.

  9. Fig. 17.2

  10. Erythrocytes-Red Blood Corpuscles • Characteristics: biconcave shape, ~7.5 mm diameter • Function: respiratory gas transport via binding/unbinding to hemoglobin (O2 and CO2) • Hemoglobin: protein globin + heme pigment • contained within erythrocytes • 4 globin subunits/Hb; each one has 1 heme that binds 1 O2 molecule

  11. Oxygen-Hemoglobin dissociation curve

  12. Erythrocytes • Erythropoesis:genesis of red blood cells • begins with hemocytoblast stem cell • stimulated by erythropoetin released from the kidneys • erythropoetin (EPO)-glycoprotein hormone released predominantly from the kidneys but also from the liver • Recombinant products: Epogen or procrit.

  13. Fig 17.6

  14. Erythrocytes • Fate and Destruction: • life time- 100-120 days • degraded in the spleen,liver by macrophages • iron released from heme and recycled • remainder of heme-degraded to  converted to bile by the liver

  15. Leukocytes- White blood cells • Granulocytes- contain cytoplasmic granules that stain with Wright’s stain; often lobed nuclei • neutrophils- most numerous WBCs; also called (polymorphonucleocytes) • function in inflammation and destroy bacteria via defensins (proteins) and phagocytosis • eosinophils- attack parasitic worms by releasing enzymes from granules, also destroys Ag/Ab complexes. • basophils- release the inflammatory chemical histamine from granules

  16. Leukocytes-White blood cells • Agranulocytes- lack visible cytoplasmic granules • spherical or kidney-shaped nuclei • lymphocytes- most live in lymphoid tissue, but some circulate in the blood • T & B lymphocytes • monocytes-differentiate into macrophages within tissues • (phagocytic cells)

  17. Production of Leukocytes • Hemocytoblast Myeloid stem cell • Lymphoid stem cell

  18. Platelets • Platelets: cytoplasmic fragments of megakaryocytes that play a role in blood clot formation • also called thrombrocytes • Production of platelets: stimulated by thrombopoietin (Tpo) • Hemocytoblast Megakaryocyte platelets fragmentation

  19. Hemostasis- Complex series of reactions that stop bleeding after a blood vessel is injured; involves numerous clotting factors (including fibrinogen, prothrombin, Ca2+)

  20. optional

  21. Blood Types optional reading pp 654-658

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