Clotting of blood is considered as the defense mechanism because of following reasons ,
1.It protect the body against the blood loss which can lead to dehydration .
2.It prevent the entry of micro organisms into the blood circulation.
Given below are the main steps of resting blood,
1. Vasoconstriction
Amount of blood which flow along the blood vesicle is reduce
2. Platelet plug formation
Platelets in the damage vesicle adhere with each other and form a mass of platelets which adhere to the vesicle wall that damage.
3. Blood clot formation
Thermoplastin is released by ruptured platelet. It converts plasma protein , prothombin to thrombin . Thrombin converts water soluble plasma protein , fibrinogen to water insoluble fibrin threads . This fibrin threads strengthen the platelet plug and forms a sticky network. RBC and WBC are trapted in fibrin network and form the blood clot. When the blood clot is formed bleeding is completely arrested .
4. Reconstruction of blood vesicle
Later blood clot is dissolve and vesicle is reconstructed by wound healing mechanism.
Edited by Tashenka Ninel