Tag: soldiers of defense

Factor VIII is an important blood clotting protein, which is also known as anti-haemophilic factor (AHF), encoded by the F$ _{8}$ gene.
Factor VIII circulates in the bloodstream in an inactive form, bound to another molecule, called Von Willebrand factor, until an injury that damages the blood vessels occurs. When injury occurs, the factor VIII is activated and separates from Von Willebrand factor. The active protein interacts with another coagulation factor, called factor IX. This interaction leads to a chain of additional reactions, that form a blood clot.

When there is an injury and blood is shed, the platelets disintegrate and liberate thromboplastin or factor III. Certain amount of thromboplastin is also derived from the damaged tissues of the injured locality.
Thromboplastin converts prothrombin into thrombin with the help of calcium ions and thrombin interacts with fibrinogen forming fibrin. This is clot.
Calcium is the Factor IV and it acts as a co-factor in the coagulation process.
Thus, the correct answer is option (B).

The presence of calcium and other clotting factors, Factor X activates an enzyme called prothrombin activator. The enzyme prothrombin activator then converts plasma protein prothrombin into thrombin. Thrombin is the enzyme which in turn converts fibrinogen into fibrin. Polymerized fibrin together with platelets(corpuscles) forms a clot at the wound site. Hence blood clot is mainly due to fibrin and corpuscles.

The mechanism of blood clotting involves the presence of calcium and other clotting factors, Factor X activates an enzyme called prothrombin activator. The enzyme prothrombin activator then converts plasma protein prothrombin into thrombin. Thrombin is the enzyme which in turn converts fibrinogen into fibrin. Polymerized fibrin together with platelets forms a clot at the wound site. The prothrombin is a plasma protein synthesized in the liver. Vitamin K is essential for the synthesis of prothrombin.

Thromboplastin is a plasma protein aiding blood coagulation through catalyzing the conversion of prothrombin to thrombin. It is a complex enzyme that is found in brain, lung, and other tissues and especially in blood platelets and that functions in the conversion of prothrombin to thrombin in the clotting of blood—called also thrombokinase.

Fibrinolysis is a process that prevents blood clots from growing and becoming problematic. This process has two types: primary fibrinolysis and secondary fibrinolysis. The primary type is a normal body process, whereas secondary fibrinolysis is the breakdown of clots due to a medicine, a medical disorder, or some other causes. In fibrinolysis, a fibrin clot, the product of coagulation, is broken down. Its main enzyme plasmin cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteases or by the kidney and liver. Hence Enzyme causing lysis of fibrin during fibrinolysis is plasmin.

So, the correct answer is 'Plasmin'.

Thrombokinase is also known as thromboplastin. It is a complex enzyme which aids in clotting of blood. It is present in platelets and some body tissues. When the platelets aggregate at the site of injury, thrombokinase is released from platelets and damaged tissues. Thrombokinase converts prothrombin into thrombin which acts as an enzyme and converts fibrinogen into fibrin threads. The fibrin threads form a clot at the site of injury. Hence thrombokinase is produced in blood clotting.