Blood

LECTURE OUTLINE

I. FUNCTIONS AND COMPOSITION OF THE BLOOD 

   A. Multiple functions of the blood
     1. Transport of O2, CO2, hormones, nutrients and metabolites; 
         pH regulation; immune responses; thermoregulation; urine 
         formation
 
  B. Cellular and Non-cellular Blood Composition 
     1. Cellular components (Red and White Blood Cells)
          a. Hematocrit
     2. Non-cellular components 

   C. Plasma characteristics
     1. Plasma proteins 

II. ERYTHROCYTES (Red Blood Cells, RBC)  

   A. Physical and biological characteristics
      1. Characteristics of RBCs
      2. RBCs contain hemoglobin
   B. Development of the RBC's
     1. Regulation by erythropoientin
   C. Environmental effects on blood function: Altitude and exercise

III. LEUKOCYTES (White Blood Cells, WBC)

   A. Functions of the WBC in immune responses
     1. Neutrophils (no stain), eosinophils (acid stain), basophils (basic 
         stain), monocytes, and B and T lymphocytes 
     2. Regulation by Colony-stimulating factors

IV. PLATELETS

   A. How do platelets form?
      1. Megakaryocyte
      2. Regulation by Thrombopoietin

V. BLOOD CLOTTING MECHANISM 

   A. The Blood Clot
   B. Platelet Aggregation
     1. What are the first steps in formation of a clot?
     2. Factors influencing clot initation
   C. Clot mechanism
     1. Roles of:  Active factors (IX through XIII), thrombin, and fibrin
          a. A cascade of events results in formation of a clot
          b. Thrombin has a number of functions: 
               * more platelet aggregration
               * activation of more thrombin
               * fibrin formation and cross-linking of fibrin
  C. Dissolution of the clot:  Roles of plasmin and WBC 

VI. MEDICAL NOTES (if time permits)

   A. Anemia has many causes
       1. For example, sickle cell anemia 
   B. Hemophilia (A and B)
      1. Queen Victoria
   C. Mononucleosis 

BASIC FACTS AND TERMS
1. Blood serves a number of functions. Can you list at least 6 of these functions?

2. Identify each major blood constituent and give its function (See Figure 16-1). What are the cellular elements of blood. Non-cellular element? How does plasma differ from serum?

3. What is average blood volume for women? Men?

4. What is hematocrit? What is a normal hematocrit? Under what conditions does hematocrit increase? Decrease?

5. Define and given the physiological significance (how or why it is important) for the following terms:
   
   • Fibrin
     
   • Albumen
     
   • Globulins (alpha, beta, and gamma)
     
   • Carbonic anhydrase
     
   • Hemolysis
     
   • Plasmin
     
   • Thrombus
     
   • Tissue factor (=Thromboplastin)
     
   • Colony-stimulating factor
     
   • Thrombopoietin
     
   • Megakaryocyte
     
   • Cytokine
     
   
   
6. Define erythropoiesis. What factors increase or decrease erythropoiesis? By what mechanisms?

7. How are platelets formed? What is their role in the blood clot mechanism? What factor prevents clot formation in a healthy vessel?

8. What are the causes and the functional characteristics for the following: Nutritional anemia, aplastic anemia, pernicious anemia, sickle-cell anemia, and hemophilia? (see Table 16-3)

9. Review the general process of clot formation (See Fig.16-12). What is the mechanism for dissolving a blood clot? Contrast the intrinsic and extrinsic pathways of clot formation.

   
   CONCEPTS

10. What is the effect of exercise on effective blood volume (that which is in circulation) and hematocrit? What changes occur in the blood when a person travels from a low altitude to a high altitude?

11. A person has a hematocrit of 62. Can you conclude from this finding that the person has polycythemia due to increased numbers of red blood cells? Explain.

12. What feedback mechanism regulates the formation of new RBC's? Why do RBC's have a short life span?

13. What is blood doping? What does the physiology of the individual change following blood doping?

14. How is iron aborbed, stored, and used by the body (see Figure 16-7)?

15. Review Tables 16-4 and 16-5 for general ideas, but don't memorize them.

16. Thrombin has a central role in the clotting mechanism. What is Thrombin and what are its multiple functions? How is positive feedback involved in some of these functions? Why have these positive feedback loops?

    
    REASONING AND PROBLEM SOLVING

17. An aspirin a day is recommended for older people to "thin" the blood and reduce heart attack risk. One action of aspirin is to reduce platelet aggregation. How would this effect reduce the risk of heart attack?

18. Following implantation of a stent in coronary artery, a patient is placed on a blood thinner, such as Plavix, to lower the risk of clot formation. Given your understanding of the clot formation mechanism, propose three or four different mechanisms by which Plavix might act? Click here for the actual Plavix mechanism.
19. Read about the role of Vitamin K in the clot mechanism in the text. Why are patients on thrombolytic drugs (those that dissolve blood clots) asked to take daily vitamin supplements lacking Vitamin K as well as restrict eating foods rich in Vitamin K, such as cabbage, brocchli, and liver? Warfarin (=Coumadin), which is the most common anticoagulant, antagonizes Vitamin K action. How would that effect explain Warfarin's anticoagulant action?