ABSTRACT
A complex mechanism is well developed in man to prevent blood loss when the vascular wall is damaged. Under certain abnormal conditions, there may be an exaggerated response of the hemostatic mechanism to vascular injury leading to the beginning of a thrombotic process. Hemostasis is achieved by three separate processes: the vascular contraction, platelet adhesion and aggregation, and blood coagulation. Among the stimuli that can elicit active vascular contractions, trauma produces the strongest response, contributing to an important element of the initial phase. The secretion of platelet granules also releases their contents which participate in the process of both platelet aggregation and blood coagulation. When the blood vessel wall is injured, there are multiple mechanisms that can directly cause platelet aggregation and secretion of its granules. Thrombin generated from the activation of the blood coagulation process can also directly induce platelet aggregation.
