Anatomy and Physiology Exam 3 Questions and Correct Answers.

Anatomy and Physiology Exam 3 Questions and Correct Answers. 1. Describe the composition and physical characteristics of whole blood. Explain why it is classified as a connective tissue. Blood is a transport fluid of the body, and is 55% plasma (water, proteins, and waste) and 45% forced elements, which are much denser. These are the RBC’s (millions) and WBC’s (thousands). So if you centrifuge it, the densest RBC’s move to the bottom, the WBC’s move to the middle, and the plasma is on the surface. Connective because it arises from the mesoderm 2. List eight functions of blood. Transport oxygen, waste, gases, nutrients, hormones, maintain BP, maintain pH, immune defense. 3. Discuss the composition and functions of plasma. Plasma is mostly water (92%) and proteins, like albumin. Rest is an insignificant waste products 4. Describe the structure, function, and production of erythrocytes. These are red blood cells. The structure is they lack all organelles, meaning no mitochondria, so no use of oxygen. They are concave discs with high surface are to maximize oxygen binding. They just transport oxygen on their many hemoglobin molecules. Erythopoesis is the body’s production of RBC in the bone marrow. Hypoxia stimulates it via EPO (hormone) release from the kidneys. Erythopoesis rate is measured via amount of reticulocytes in the circulation (these are immature RBC’s). Because they have a lifespan of 120 days, they are continuously destroyed and remade. 5. Describe the chemical makeup of hemoglobin. Transporter of oxygen in RBC. Millions in each RBC, and they have 4 iron carrying subunits that carry an oxygen molecule each. 6. Give examples of disorders caused by abnormalities of erythrocytes. Explain what goes wrong in each disorder. Anemia is characterized by a low RBC amount or hemoglobin, usually from low iron intake, increases iron loss, or massive blood loss. Polycythemia is an unnatural high RBC count. Can be from high altitude training (body adapts to the low oxygen in the air) or from blood doping (introduce RBC into the body with drugs.) Sickle cell is an autoimmune disorder where the RBC is altered via one amino acid change (glutamate to valine) and this leads to a sickle shape in the RBC. This decreases surface are tremendously, thus oxygen carrying capacity is lowered significantly. Tony Berardi 2 7. List the classes, structural characteristics, and functions of leukocytes. The body contains a much smaller amount of theses, divided into neutrophils (60%ish), eisonophils, basophils, monocytes, lymphocytes (25%ish). Two class: granular (-ophil ones) and agranular. Neutrophils digest all bacteria, eisonophils are for parasites and allergy, basophils are for inflammatory, monocytes are the major phagocyets for debris in the body, and the lymphocytes are the B and T cells in the immune system (specific immune responses to disease). Too many lymphocytes means a viral infection~leukocyotosis. Too liitle is leucopenia, and is a sign of malnutrition or some disease that attacks leukocytes.  They have the usual organelles, but no hemoglobin, meaning they are not for oxygen transport. 8. Describe how leukocytes are produced. You start with a stem cell in the bone marrow, this turns into a myeloid stem cells, then into colony forming granule cells, and then to all the granular leukocytes. The agranular form via lymphoid stem cells. 9. Describe the structure and function of platelets. These serve to cover damaged areas and repair them. They arise from a huge cell called a megakaryocyte. This will split in the bone marrow to many platelets, which have no nucleus. Very short life span. 10. Describe the processes of hemostasis. List factors that limit clot formation and prevent undesirable clotting. This is the process of the body to stop bleeding. So first say a vessel is damaged: first the vessel will constrict (called vascular spasm). Then those platelets will adhere to the damaged area to from a plug. Then finally there will be clotting via certain proteins in the blood. Clotting is called coagulation, and it’s a huge cascade that will eventually lead to an insoluble clot. Fibrin, another protein in the plasma, wraps the platelets’ into a mesh Two pathways are worth noting: An extrinsic, which is simpler. A trauma to the tissue leads to a release of tissue factor and this will activate factor X. This will cause prothrombin to become thrombin, and then fibrinogen to fibrin. The intrinsic is slower and eventually leads to factor X activation. So they both have a common point. Calcium is important for this mechanism. An undesirable clot is called thrombosis, or a thrombus. The body has a mechanism called fibrinolysis to dissolve unwanted clots. This is done through the molecule plasmin.