Anatomy Chapter 14

31. Explain how hemostasis follows a positive feedback cycle.

Once a blood clot starts to form, it promotes still more clotting. This is due to the fact that thrombin also acts directly on blood-clotting factors other than fibrinogen. It can cause prothrombin to form still more thrombin.

33. Explain how a blood clot may be removed naturally from a blood vessel.

Fibrin threads absorb a plasma protein called plasminogen. Then a substance called plasminogen activator is released from the lysosomes of the damaged tissue cells that convert plasminogen to plasmin. Plasmin is a protein-splitting enzyme that can digest fibrin threads and other proteins associated with blood clots

27. Explain the importance of vitamin K in hemostasis.

Vitamin K is important for some clotting functions to happen

antibody

a blood protein produced in response to counteracting a specific antigen. Antibodies combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood

antigen

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies

19. Describe the function of the following plasma proteins.

a. Albumins— help to maintain osmotic pressure of the blood. b. Globulins— help to transmit lipids and fat-soluble vitamins and are the antibodies of immunity. c. Fibrinogen— precursor to fibrin that has a major role in blood clotting.

Briefly describe the life cycle of a red blood cell from differentiation through destruction and recycling.

a. Nutrients from food are absorbed from the small intestine into the bloodstream. b. The blood transports the absorbed nutrients to the red bone marrow tissue. c. The red bone marrow produces red blood cells. d. The red blood cells circulate for about 120 days. e. Damaged and old red blood cells are destroyed in the liver. f. The resulting biliverdin is converted to bilirubin that is excreted in the bile from the liver.

38. Explain why a person with blood type AB is sometimes called a universal recipient and why a person with blood type O is sometimes called a universal donor.

-People with AB blood are sometimes called universal recipients because Group AB - has both A and B antigens on red cells (but neither A nor B antibody in the plasma -Group O - has neither A nor B antigens on red cells (but both A and B antibody are in the plasma

1. List at least three major functions of blood

1. Connective tissue 2. Transports vital substances 3. Maintains stability of interstitial fluid 4. Distributes heat

2. List the three formed elements in blood.

1. Red blood cells 2. White blood cells 3. Platelets

14. Distinguish between granulocytes and agranulocytes.

A granulocyte is a white blood cell that has granular cytoplasm. Agranulocytes are white blood cells that lack cytoplasmic granules.

5. Indicate where blood cells differentiate, and explain the role of hematopoietic stem cells.

A stem cell can divide to give rise to specialize (more differentiated) cells as well as more stem cells. As hematopoietic stem cells divide, the new cells, myeloid and lymphoid stem cells, respond to different secreted growth factors called hematopoietic growth factors that turn on some genes and turn off others. The exposure to growth factors ultimately sculpts the distinctive formed elements of blood, including the cellular components of the immune system.

34. Distinguish between a thrombus and an embolus.

A thrombus is a blood clot that forms in a vessel abnormally. An embolus is a blood clot that becomes dislodged and is carried away by blood flow.

15. List the five types of leukocytes and the major functions of each.

A. Basophils are granulocytes that function to release heparin that inhibits blood clotting. They also release histamine to cause inflammation. B. Eosinophils are granulocytes that function to kill certain parasites and help control allergic reactions. C. Neutrophils are granulocytes that function to phagocytize foreign particles. d. Monocytes are agranulocytes that leave the bloodstream to function as macrophages that phagocytize foreign particles. e. Lymphocytes are agranulocytes that function to produce antibodies that act against specific foreign substances.

11. Explain how vitamin B12 deficiency affects red blood cell production.

B12 and folic acid deficiency are both required for DNA synthesis that is needed by all cells for growth and reproduction. Hematopoietic tissue reproduces at a particularly high rate, so this tissue is especially affected by the lack of either vitamin.

42. Describe erythroblastosis fetalis, and explain how this condition may develop.

Erythroblastosis fetalis is a condition where an Rh-positive fetus has come into contact with anti-Rh antibodies through breaks in the placental membrane. This only happens if the mother has previously had a child that was Rh-positive. The baby's blood may agglutinate after birth

10. Define erythropoietin, and explain its function.

Erythropoietin is a hormone that is released from the kidneys, and to a lesser extent the liver, which stimulates red blood cell production.

28. Distinguish between fibrinogen and fibrin

Fibrinogen a soluble protein present in blood plasma, from which fibrin is produced by the action of the enzyme thrombin. Fibrin an insoluble protein formed from fibrinogen during the clotting of blood. It forms a fibrous mesh that impedes the flow of blood

20. Identify the major gases and nutrients in plasma.

Gases in plasma include oxygen, carbon dioxide, and nitrogen. Plasma nutrients include amino acids, simple sugars, and lipids.

32. Define serum.

Serum is essentially plasma minus all of its fibrinogen and most of the other clotting factors.

22. Identify the two most abundant plasma electrolytes, as well as three minor plasma electrolytes.

Sodium and chloride are the two most abundant plasma electrolytes Magnesium, chloride, bicarbonate are three minor plasma electrolytes

3. Define hematocrit, and explain how it is determined.

The hematocrit measures the volume of red blood cells compared to the total blood volume (red blood cells and plasma). The normal hematocrit for men is 40 to 54%; for women it is 36 to 48%. This value can be determined directly by microhematocrit centrifugation or calculated indirectly.

29. Indicate the trigger and outline the major steps for extrinsic clotting and for intrinsic clotting.

The trigger for extrinsic clotting is the blood vessel wall or tissue outside the blood vessels contracting. The intrinsic clotting factors are all within the blood proper. The trigger is exposure of the blood to a foreign surface such as collagen.