What is the sequence of blood clotting from the wound to forming a scab?
1 Answer
The process of stopping bleeding after injury involves three events - blood vessel spasm, formation of platelet plug, and blood coagulation.
Explanation:
Injury to a blood vessel brings the blood flow in contact with the outside of the vessel. Platelets present in the blood bind to specific membrane receptors outside the interrupted endothelium.
This activates platelets integrin, which result in the tight binding of the platelets to the extracellular matrix. These activated platelets release their contents into the blood plasma activating more platelets in the blood.
Fibrinogen and glycoproteins cause adjacent platelets to clump together. Later thrombin is produced and it converts fibrinogen to fibrin, forming a mesh with platelets. This plugs the break in the blood vessel wall.
Within minutes the fibrin mesh begins to contract, squeezing out its fluid contents. This is the last stage of coagulation and is called as clot retraction.
It yields a resilient insoluble clot that can withstand the friction of blood flow.
