What is the primary function of von Willebrand factor?

Von Willebrand factor plays a crucial role in hemostasis, specifically in the process of platelet adhesion to sites of vascular injury. It acts as a bridging molecule that connects platelets to the exposed collagen in the damaged endothelium. This interaction is essential for the formation of a platelet plug, which is one of the first steps in preventing bleeding. When blood vessels are injured, von Willebrand factor is released from endothelial cells and platelets, thereby promoting platelet aggregation and helping maintain vascular integrity.

This function is particularly important in conditions where blood vessels are injured, allowing for rapid response to prevent excessive blood loss. While erythrocyte aggregation, thrombin inhibition, and fibrinogen conversion are all vital aspects of hemostasis, they do not directly relate to the primary role of von Willebrand factor, which is focused on facilitating the initial adhesion of platelets.