Platelet activation pathophysiology

Platelet activation is a key part of blood clotting. When a blood vessel is injured, underlying tissues release signals that alert platelets, small blood cells, to the site. These signals cause platelets to change shape, stick to each other, and release chemical messengers that recruit more platelets. This process forms a platelet plug to seal the wound. Activation also triggers a cascade of reactions that strengthen the clot with fibrin, a protein that creates a stable mesh. Proper regulation ensures clots form when needed to prevent bleeding, while avoiding excessive clotting that could block blood flow.