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It is the process of maintaining blood in a liquid form, prevents excess loss of blood from trauma or disease by forming a hemostatic plug and removal of this plug when healing is complete. To balance the forces which cause blood to solidify or to remain fluid involves several interacting systems. This process involves the following coagulation mechanisms.1

  • Vascular constriction: When the blood vessel ruptures, the wall of the vessel contracts immediately to reduce bleeding.
  • Platelet plug formation: Platelet plug is formed when the trauma to the blood vessel is very small or in case of minute damages that happen to the body everyday.
  • Blood clot formation as a result of blood coagulation.

The blood takes 15–20 sec to begin the clot formation if the trauma is severe and 1–2 min to develop the clot if the trauma is less severe or minor.2

In the process of coagulation more than 50 substances are involved. Coagulation is initiated by one of the following: 

  • Trauma to the vascular wall and adjacent tissues.
  • Trauma to the blood
  • Contact of the blood with damaged endothelial cells, collagen and other tissue elements outside the blood vessel.

The above instances lead to the formation of prothrombin activator, which converts prothrombin to thrombin.

Prothrombin activator is usually formed in two ways.3

  • Extrinsic pathway, which begins with trauma to the vascular walls and surrounding tissues.
  • Intrinsic pathway, which begins in the blood itself.

In both the pathways, blood-clotting factors (inactive forms of proteolytic enzymes) play a major role. When they are converted to active forms, they cause the cascade reactions of the clotting process, which leads to clot formation.


What is Blood Clot?

The blood clot is composed of a meshwork of fibrin fibers, which run in all directions and enclose the blood cells, platelets and plasma.
  • Growth of fibrous tissue into the clot opening in the vessel.
  • Finally, the fibrous tissue grows and invades the clot.

The same clotting mechanism when deficient leads to bleeding disorders and in excess, leads to clot formation inside the body.

Thus, hemostasis play an important role in maintaining the balance between blood being in a fluid state and clot formation, and prevention of excess bleeding in case of injuries.


Hemostasis is an important physiological process of our body, which maintains the balance between blood being in a fluid state and clot formation and prevention of excess bleeding in case of injuries. It is a complex mechanism involving several components and processes. Derangements in these components like the clotting factors can cause bleeding disorders, which could even be fatal. Hence, the need for the proper functioning to the hemostatic mechanism cannot be overemphasized.

Related article in Hemostasis

Written by Healthplus24 team
Date last updated: May 24, 2011