First step in initiation of primary hemostasis for clot formation is?
Ans. is 'b' i.e., Vasoconstriction Steps in hemostasis at the site of injuryi) Vasconstriction* Immediate hemostasis following injury is achieved by brief arteriolar vasoconstriction. It is due to reflex neurogenic mechanism. This effect is transient.ii) Primary hemostasis* It is achieved by formation of primary hemostatic plug (platelet plug). Following injury to endothelium, thrombogenic subendothelial matrix is exposed and allows the platelets to adhere with collagen of ECM. These platelets are activated and recruit other platelets by their secretions.iii) Secondary hemostasis* Activation of coagulation (clotting) system leads to formation of secondary hemostatic plug (definitive plug or fibrin clot) which is composed offibrin, platelets, RBCs, and thrombin.iv) Dissolution of clot* Activation of fibrinolytic system results in dissolution of clot.
Fibrin deposition
Vasoconstriction
Platelet adhesion
Thrombosis
Blood