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Chapter 19, part 1

Chapter 19, part 1. Blood. Learning Objectives. List the components of the cardiovascular system and explain the major functions of this system. Describe the important components and major functions of the blood List the characteristics and functions of red blood cells.

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Chapter 19, part 1

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  1. Chapter 19, part 1 Blood

  2. Learning Objectives • List the components of the cardiovascular system and explain the major functions of this system. • Describe the important components and major functions of the blood • List the characteristics and functions of red blood cells. • Describe the structure of hemoglobin and indicate its functions. • Discuss red blood cell production and maturation.

  3. Learning Objectives • Explain the importance of blood typing and the basis for ABO and Rh incompatibilities. • Categorize the various white blood cells on the basis of structure and function. • Describe the structure, function and production of platelets. • Describe the reaction sequences responsible for blood clotting.

  4. SECTION 19-1The Cardiovascular System: An Introduction

  5. The cardiovascular system • Provides a mechanism for rapid transport of nutrients, waste products, respiratory gases and cells

  6. SECTION 19-2Functions and Composition of Blood

  7. Blood • Fluid connective tissue • Functions include • Transporting dissolved gases, nutrients, hormones, and metabolic wastes • Regulating pH and ion composition of interstitial fluids • Restricting fluid loss at injury sites • Defending the body against toxins and pathogens • Regulating body temperature by absorbing and redistributing heat

  8. The composition of blood • Plasma and formed elements comprise whole blood • Red blood cells (RBC) • White blood cells (WBC) • Platelets • Can fractionate whole blood for analytical or clinical purposes

  9. Figure 19.1 The Composition of Whole Blood Figure 19.1a

  10. Figure 19.1 The Composition of Whole Blood Figure 19.1b

  11. Figure 19.1 The Composition of Whole Blood Figure 19.1c

  12. Hemopoiesis • Process of blood cell formation • Hemocytoblasts are circulating stem cells that divide to form all types of blood cells • Whole blood from anywhere in the body has roughly the same temperature, pH and viscosity

  13. SECTION 19-3Plasma

  14. Plasma • Accounts for 46-63% of blood volume • 92% of plasma is water • Higher concentration of dissolved oxygen and dissolved proteins than interstitial fluid

  15. Plasma proteins • more than 90% are synthesized in the liver • Albumins • 60% of plasma proteins • Responsible for viscosity and osmotic pressure of blood

  16. Additional Plasma Proteins • Globulins • ~35% of plasma proteins • Include immunoglobins which attack foreign proteins and pathogens • Include transport globulins which bind ions, hormones and other compounds • Fibrinogen • Converted to fibrin during clotting • Removal of fibrinogen leaves serum

  17. SECTION 19-4Red Blood Cells

  18. Abundance of RBCs • Erythrocytes account for slightly less than half the blood volume, and 99.9% of the formed elements • Hematocrit measures the percentage of whole blood occupied by formed elements • Commonly referred to as the volume of packed red cells

  19. Structure of RBCs • Biconcave disc, providing a large surface to volume ration • Shape allows RBCs to stack, bend and flex • RBCs lack organelles • Typically degenerate in about 120 days.

  20. Figure 19.2 The Anatomy of Red Blood Cells Figure 19.2

  21. Hemoglobin • Molecules of hemoglobin account for 95% of the proteins in RBCs • Hemoglobin is a globular protein, formed from two pairs of polypeptide subunits • Each subunit contains a molecule of heme which reversibly binds an oxygen molecule • Damaged or dead RBCs are recycled by phagocytes

  22. Figure 19.3 The Structure of Hemoglobin Figure 19.3

  23. Figure 19.4 “Sickling” in Red Blood Cells Figure 19.4

  24. RBC life span and circulation • Replaced at a rate of approximately 3 million new blood cells entering the circulation per second. • Replaced before they hemolyze • Components of hemoglobin individually recycled • Heme stripped of iron and converted to biliverdin, then bilirubin • Iron is recycled by being stored in phagocytes, or transported throughout the blood stream bound to transferrin

  25. Figure 19.5 Red Blood Cell Turnover Figure 19.5

  26. RBC Production • Erythropoeisis = the formation of new red blood cells • Occurs in red bone marrow • Process speeds up with in the presence of EPO (Erythropoeisis stimulating hormone) • RBCs pass through reticulocyte and erythroblast stages

  27. Figure 19.6 Stages of RBC Maturation Figure 19.6

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