Which of the following is responsible for adhesion of plate!lets to the vessel IN all?(.4//MS May 2015, November 2013
**Core Concept**
The process of platelet adhesion to the vessel wall is a critical step in the formation of a hemostatic plug. It involves the interaction between platelets and the subendothelial matrix, which is rich in collagen. The adhesion of platelets to the vessel wall is mediated by specific receptors on the platelet surface.
**Why the Correct Answer is Right**
The correct answer is von Willebrand factor (vWF). vWF is a large, multimeric protein produced by endothelial cells that binds to collagen in the subendothelial matrix. It also binds to the platelet surface receptor, glycoprotein Ib (GPIb), which triggers platelet activation and adhesion to the vessel wall. The binding of vWF to collagen and GPIb is essential for the initiation of platelet plug formation.
**Why Each Wrong Option is Incorrect**
**Option A:** Fibrinogen is involved in platelet aggregation, but not adhesion to the vessel wall.
**Option B:** Thromboxane A2 is a prostanoid produced by platelets that promotes platelet activation and aggregation, but it is not directly involved in platelet adhesion.
**Option C:** Glycoprotein IIb/IIIa (GPIIb/IIIa) is a platelet receptor that binds to fibrinogen and other ligands, facilitating platelet aggregation, but it is not responsible for adhesion to the vessel wall.
**Clinical Pearl / High-Yield Fact**
The von Willebrand factor (vWF) gene mutation is responsible for von Willebrand disease, a bleeding disorder characterized by impaired platelet adhesion and aggregation.
**Correct Answer:** C. von Willebrand factor.