Whenever we are injured, blood starts oozing out of it, after sometime it automatically stops. Just think what would happen if it didn’t miraculously stop. We would bleed to death even by the smallest of cuts if our blood wouldn’t have clotted.
Clotting of blood is a very important mechanism of our body. There are people who suffer from hemophilia, where their blood doesn’t clot normally, it takes longer than normal and there are chances of internal bleeding as well.
Blood basically consist of three types of cells: red blood cells (erythrocytes), white blood cells (leucocytes) and platelets.
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The RCBs essentially carry and supply oxygen to different parts of the body.
The WBCs defend our body from the invasion of disease –causing organisms.
Platelets are the type of blood cells which play an important role in the clotting of blood.
All these cells are afloat in a liquid called plasma. Plasma contains various types of proteins and some of them are called as clotting factors.
Whenever a blood vessel breaks, platelets gather there and help seal off the leak temporarily. For permanent sealing they need the help of these clotting factors.
MECHANISM:
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Whenever bleeding occurs, the platelets and the blood proteins become activated through some chemical reactions. These activated platelets are sticky and they adhere to the walls of the broken blood vessels and form a white clot. Whenever the bleeding occurs, the damaged tissues secrete an enzyme called thrombokinase. This enzyme converts prothrombin (a soluble protein in blood) into thrombin. The activated blood proteins start a chain of chemical reactions which results in the production of a substance called fibrin. Fibrin are similar to long sticky strands and it sticks to the broken blood vessel’s wall, forming a web like structure. Red blood cells get caught up in this web and a red clot (mature clot) is formed. The fibrin strands binds the platelet together and tights it make a stable clot.
In arteries the clotting mechanism majorly depends upon platelets whereas in veins, it majorly depends upon the fibrin, although in either of mechanisms both of them are involved but in different amounts.