<prompt> During homeostasis, platelet affects the coagulation area :Platelet adhesion to exposed endotheliumClot retractionActivation of prothrombinase complexAll  <response>: 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 dt 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 complex2 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 dt growth factors secreted by platelet- Clot retraction contraction dt contractile proteins actin, myosin and thrombosthenin 