Question

Write the main steps in coagulation of blood in their correct sequence?

Answer 1

Clotting or coagulation refers to converting liquid blood into a jelly-like substance. It occurs in the following steps:

1. The injured tissue cells and the platelets, which disintegrate at the site of the wound release a substance thrombokinase (also called thromboplastin). (More recently it is called "Factor X" or Stuart factor).
2. The thrombokinase acts as an enzyme and with the help of the calcium ions present in the plasma, it converts a substance prothrombin (inactive) of the plasma, into thrombin (active). Vitamin K, a fat-soluble vitamin, is essential for the production of prothrombin.
3. Thrombin, in the presence of calcium ions, reacts with the soluble fibrinogen of the plasma to convert it into insoluble fibrin. Fibrin is a solid substance that forms threads. These microscopic threads of fibrin are sticky and form a network (mesh) at the wound.
4. Blood cells are trapped in the network of the fibrin; the network then shrinks and squeezes out the rest of the plasma which is in the form of a clear liquid, the serum. The solid mass which is left behind is called dot (or thrombus).