A) Heparin and calcium ions
B) Calcium ions and platelet factors
C) Oxilates and citrates
D) Platelet factors and heparin
Correct Answer: B
Solution :
Coagulation or clotting of blood itself is a complex cascade of reaction involving calcium ions platelets, enzymes and structural proteins. This cascade begins from thirty seconds to several minutes after the injury. Coagulation can begin with either of two pathways, called the extrinsic and intrinsic pathway, both of which feed into a common pathway that completes the process. The extrinsic pathway begins with a substances called tissue factor (tissue thromboplastin) released by damaged blood vessels and surrounding tissues. In the presence of other plasma proteins (clotting factors) and calcium ions, this leads to the activation of a protein called factor X. The intrinsic pathway begins with a substance called factor XII released by blood platelets. Through a series of additional clotting factors and again in the presence of calcium ions, this pathway also leads to the activation of factor X. One of the necessary factors of the intrinsic pathway is called factor VIII. The common pathway begins with the activation of factor X. In the presence of calcium ions and other clotting factors, factor X activates an enzyme called prothrombin activators. This enzyme then converts the plasma protein prothrombin into thrombin. Thrombin is an enzyme that, in turn, converts fibrinogen to fibrin. Here, the cascade ends. Fibrin forms strands that stick to the platelets and endothelial cells at the wound forming a meshwork that, in turn, traps other cells resulting in blood clot.
You need to login to perform this action.
You will be redirected in
3 sec
