What does platelet adhesion refer to?

Platelet adhesion is a critical process in hemostasis, wherein platelets attach themselves to the endothelial surface of blood vessels, particularly to subendothelial structures like collagen. When there is damage to the vascular endothelium, collagen fibers become exposed, which serve as a site for platelets to bind. This adhesion is facilitated by specific receptors on the platelet surface, notably glycoprotein Ib (GPIb), which interacts with von Willebrand factor that bridges the platelets to the collagen.

This initial attachment is essential for the subsequent steps of hemostasis, including platelet activation and aggregation, which ultimately lead to the formation of a platelet plug that helps prevent excessive bleeding. Understanding platelet adhesion is fundamental in the context of coagulation and vascular injury response, as it highlights the importance of the interaction between platelets and the extracellular matrix in maintaining hemostatic balance.