Q.What is Erythropoisis?
Erythropoiesis is the process by which red blood cells (erythrocytes) are produced. It is stimulated by decreased O2 in circulation, which is detected by the kidneys, which then secrete the hormone erythropoietin.[2] This hormone stimulates proliferation and differentiation of red cell precursors, which activates increased erythropoiesis in the hemopoietic tissues, ultimately producing red blood cells.
Q.2 Role of Plasma protein in blood coagulation.
Ans: •Prothrombin: When blood vessels are damaged, vessels and nearby platelets are stimulated to release a substance called prothrombin activator, which in turn activates the conversion of prothrombin, a plasma protein, into an enzyme called thrombin. This reaction requires calcium ions.•Thrombin: Thrombin facilitates the conversion of a soluble plasma protein called fibrinogen into long insoluble fibers or threads of the protein fibrin.
•Fibrin: Fibrin threads wind around the platelet plug at the damaged area of the blood vessel, forming an interlocking network of fibers and a framework for the clot. This net of fibers traps and helps hold platelets, blood cells and other molecules tight to the site of injury, functioning as the initial clot. This temporary fibrin clot can form in less than a minute, and usually does a good job of reducing the blood flow. Next, platelets in the clot begin to shrink, tightening the clot and drawing together the vessel walls. Usually, this whole process of clot formation and tightening takes less than a half hour.
