Platelets contribute to the hemostatic
process in two different ways. First, through their
adhesive and cohesive functions that lead to the formation
of a hemostatic plug. Second, they can activate coagulation
mechanisms through the exposure of an adequate phospholipidic
surface, acting as a catalytic site for the development
of coagulation and the consolidation of the hemostatic
plug. To promote a correct hemostasis, platelets should
ideally retain their adhesive and procoagulant properties.
Platelets possess important secretory functions. During
the process of activation, platelets express internal
membrane proteins and release adhesive proteins, coagulation
and growth factors. Some of the proteins facilitate
the cross-talk of platelets with leukocytes and endothelial
cells. Thus platelets play and important role in imflamatory
and proliferative events and play a critical role for
tissue remodeling and wound healing.
The following animation shows, step by step, the physiological
process of hemostasis as it occurs in flowing blood:
(Requires Adobe Flash Player™. Click here
for free download). (For animation uses, please see Use of Content at Legal Information).