ATI Pathophysiology Practice Exam

What is a primary role of platelets in hemostasis?

1. Coagulation factor activation

2. Formation of plugs

3. Vasodilation

4. White blood cell mobilization

The correct answer is: Formation of plugs

Platelets play a crucial role in hemostasis primarily through the formation of plugs. When a blood vessel is injured, platelets are activated and adhere to the exposed site of the vessel wall. They undergo a process called degranulation, where they release various substances that promote further platelet aggregation and recruit additional platelets to the site of injury. This aggregation leads to the formation of a temporary "platelet plug," which acts as a barrier to prevent excessive blood loss until the more stable clotting process can occur. Other options such as coagulation factor activation, while related, focus on different aspects of the hemostatic process. Coagulation factors are proteins that contribute to the blood clotting cascade, but platelets themselves primarily serve to aggregate and form the physical obstruction. Vasodilation is a process that involves the widening of blood vessels, often mediated by other substances such as nitric oxide, rather than being a direct function of platelets. Lastly, while white blood cell mobilization is essential for immune responses, it is not a primary role of platelets in hemostasis.