ABSTRACT
The initiation of the hemostatic plug starts with the accumulation of platelets at the site of vessel wall injury, as the result of platelets sticking to collagen in exposed subendothelial structure. In this reaction the platelet receptor, glycoprotein Ib (GP Ib) is important as it links with von Willebrand factor to form a bridge between the platelets and collagen (Clemetson, 1995; Weiss, 1995). This platelet adhesion to the subendothelium is followed by cohesion or aggregation of the platelets whereby they bind to each other in a fibrinogen dependent reaction. This interaction is mediated by the binding of fibrinogen to GPIIb/IIIa receptor on the surface of activated platelets (Clemetson, 1995; Weiss, 1995). Collagen and the first traces of thrombin formed at the injury sites stimulate the platelet aggregation.
