NUR 633: THE HEMATOPOIETIC SYSTEM EXAM QUESTIONS AND ANSWERS

NUR 633: THE HEMATOPOIETIC SYSTEM EXAM QUESTIONS AND ANSWERS /.Elements of the Hematopoietic System - Answer-• All the blood cells and their precursors • The bone marrow, where blood cells have their origin • The lymphoid tissues where some blood cells circulate as they develop and mature • Blood is made up of Fluid/dissolved components which includes water, proteins & small molecular substances • Blood is also made up of cellular elements such as red blood cells, thrombocytes (forms clots) or platelets as well as white blood cells (Lymphocytes & Leukocytes) • RBC: the most abundant type of blood cell carries oxygen & carbon dioxide • WBC: immune and inflammatory response • Thrombocytes are cell fragments involved in blood clotting • Plasma is an extracellular fluid /.Plasma - Answer-• Assists with transport of nutrients, chemical messengers, metabolites, toxins & hormones • Helps carry RBCs to pick up O2 at the pulmonary alveoli • Assists with electrolyte & acid base balance • Aid in body defenses • Maintains body fluid through osmotic forces & prevents blood loss • Major plasma proteins are albumin, globulins & fibrinogen which are produced by the liver (except gamma globulins) /.• Albumin - Answer-• Most abundant • Comprises approximately 54% of the plasma proteins • Too large to pass through capillary pores so it stays in circulation • Because it is not excreted it aides with plasma osmotic pressure & maintains of blood volume • Serves as a carrier for different substances /.Globulins - Answer-• Comprise approximately 38% of plasma proteins • Play an important role in liver function, blood clotting, and immunity. • Three types of globulins: • Alpha globulins transport bilirubin and steroids. • Beta globulins transport iron and copper. • Gamma globulins constitute the antibodies of the immune system. /.• Fibrinogen - Answer-• Makes up approximately 7% of the plasma proteins • Soluble protein that is converted to an insoluble form-Fibrinogen- for clotting. • When clotting factors are removed from plasma the liquid that remains is serum. /.Erythrocytes - Answer-• Most abundant cell type • Life span is 120 days • Primary function is to carry oxygen to the body's tissues via hemoglobin (the oxygen caring protein) • In addition to oxygen transport RBC's transport carbon dioxide for excretion and for the regulation of acid-base balance /.Leukocytes - Answer-• WBC's make up 1% of blood volume • Produced in bone marrow and circulate via lymphoid tissues of the body • Important for defense against disease via immune response, destruction of cancer cells & the inflammatory response/wound healing • Granulocytes (contain granules) include neutrophils (maintain host defense), • Eosinophils (allergic reaction and chronic immune response), • Basophils (anticoagulation, vasodilation; involved in allergic & hypersensitivity reactions) /.• Agranulocytes: - Answer-• Lymphocytes (main functional cell of the immune system), • Monocytes (prod in bone marrow and when they leave transform into macrophages), • Macrophages (phagocytic, host defense) /.Thrombocytes (platelets) - Answer-• Circulating cell fragments of the large megakaryocytes • Function to form the platelet plug to helps control bleeding • Release mediators that are required for blood coagulation • Can not replicate, last approximately 10 days in circulation before being removed by the spleen. /.Hematopoiesis - Answer-• Hematopoiesis means the production of blood cells • Begins in the yolk sac during the second week of embryonic development, then the liver and spleen at the 2nd month. At the 7th month is when the bone marrow begins to produce blood cells • The bone marrow is the primary site of blood cell production throughout life. • Occurs mostly in the long bones in children. Flat bones of axial skeleton in adults. • Medullary hematopoiesis is blood cell production in the bone marrow • Extramedullary hematopoiesis is blood cell production that does not occur in bone marrow (liver & spleen-active during fetal development) • Extramedullary hematopoiesis occurs when the liver and spleen produce blood cells because the bone marrow is not able to produce sufficient amounts. /.Blood cell precursors - Answer-• All blood cells come from pluripotent stem cells- these are cells capable or producing several types of cells • All blood cells come from these stem cells including the erythrocyte, lymphocyte, and megakaryocyte • Pluripotent stem cells have the lifelong ability for reproduction and self-renewal • These cells develop into functionally mature cells through differentiation. • Undifferentiated pluripotent cells change into colony-forming units (CFUs) which eventually produce mature lymphocytes, myelocytes, megakaryocytes or erythrocytes. /.Hemostasis - Answer-• The stoppage of blood flow • Regulated through a complex combination of activators and inhibitors that maintain blood fluidity and prevent blood from leaving the vascular compartment • Normally works to seal the blood vessel & prevents blood loss or hemorrhage • Hemostasis is abnormal when there is inappropriate blood clotting or when there is insufficient clotting to stop blood loss • Disorders fall into 2 categories • Inappropriate clot formation (thrombosis) • Failure of blood to clot (bleeding disorders) /.Stages of Hemostasis - Answer-Vessel spasm or vascular constriction (Temporary lasting min to hours. Response to endothelial injury. TXA2 is released from cells, contributes to vasoconstriction) Formation of the platelet plug (in response to small breaks in the vessel wall which involves the activation, adhesion & aggregation of platelets. Platelet adhesion requires a protein called von Willebrand factor which is produced by endothelial cells of blood vessels. It is a carrier protein for coagulation factor VIII) Blood coagulation or development of an insoluble fibrin clot through the conversion of fibrinogen to fibrin Clot retraction which stabilizes the clot & brings the wound edges together Clot dissolution or fibrinolysis (blood clots are dissolved) /.• Conditions that create increased platelet function - Answer-Atherosclerosis Diabetes mellitus Smoking Elevated blood lipoid and cholesterol levels Increased platelet levels /.• Conditions that cause accelerated activity of the coagulation system - Answer-• Pregnancy and the puerperium • Use of oral contraceptives • Postsurgical state • Immobility • Congestive heart failure • Malignant diseases