Vérlemezkeaggregáció

Vérlemezkeaggregáció is the process by which blood platelets (thrombocytes) clump together. This is a critical step in hemostasis, the process that stops bleeding. When a blood vessel is injured, platelets are exposed to collagen and other substances, which triggers their activation. Activated platelets change shape, extend pseudopods, and adhere to the injured site. They then release granules containing various molecules, including adenosine diphosphate (ADP) and thromboxane A2, which further activate and recruit other platelets. This recruitment leads to the formation of a platelet plug, which temporarily seals the damaged vessel.

The aggregation of platelets is a complex and tightly regulated process involving various receptors and signaling pathways on the platelet surface. Key receptors involved include glycoprotein Ib (GPIb) for initial adhesion to von Willebrand factor, and glycoprotein IIb/IIIa (GPIIb/IIIa) which binds fibrinogen and facilitates platelet-platelet interactions. Disorders affecting platelet aggregation can lead to either excessive bleeding (thrombocytopenia or impaired aggregation) or abnormal clot formation (thrombosis). Medications that inhibit platelet aggregation, such as aspirin and clopidogrel, are widely used to prevent cardiovascular events like heart attacks and strokes by reducing the risk of blood clot formation. Understanding vérlemezkeaggregáció is crucial in both understanding normal hemostasis and in the management of thrombotic and bleeding disorders.