During homeostasis, platelet affects the coagulation area :
A i.e. Platelet adhesion to exposed endothelium B i.e. Clot retraction C i.e. Activation of prothrombinase complexRole of Platelets in Hemostasis- VasoconstrictionQ d/t release of TXA2 and serotonin- Adherence : The glycoprotein of cell membrane platelet cause adherence to exposed endothelium (but repulses to normal endothelium)- Platelet plug formation closing small vascular holes- Conversion of prothrombin to thrombin: Activation of prothrombinase complex+2 (consisting of platelet anionic phospholipids Ca++, factor Va, factor Xa and prothrombin) on the surface of activated platelet lit conversion of prothrombin into thrombin- Stabilization of fibrin: Fibrin stabilization factor released from platelet cause stablization of fibrin (Polymerization of fibrin)- Thrombin causes conversion of fibrinogen to fibrin- Fibrinous organization of blood clot d/t growth factors secreted by platelet- Clot retraction & contraction d/t contractile proteins actin, myosin and thrombosthenin
Platelet adhesion to exposed endothelium
Clot retraction
Activation of prothrombinase complex
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