Platelet adhesion to collagen occurs :
**Question:** Platelet adhesion to collagen occurs:
A. through von Willebrand factor (vWF)
B. primarily through glycoprotein IIb/IIIa receptor
C. through glycoprotein Ib-IX-V receptor complex
D. solely through von Willebrand factor
**Correct Answer:** .
**Core Concept:**
Platelet adhesion is a crucial step in the process of hemostasis, leading to the formation of a stable platelet plug at the site of vascular injury. Collagen, a major component of the extracellular matrix, plays a vital role in this process. When the vessel wall is injured, exposed collagen triggers platelet adhesion, activation, and aggregation.
**Why the Correct Answer is Right:**
Platelet adhesion to collagen occurs through the combined action of von Willebrand factor (vWF) and glycoprotein (GP) IIb/IIIa receptor. VWF serves as a bridge between collagen and GP IIb/IIIa receptor, which is expressed on the platelet surface. The interaction between vWF and collagen, followed by GP IIb/IIIa receptor binding to vWF, allows platelets to adhere to the damaged blood vessel wall.
**Why Each Wrong Option is Incorrect:**
A. Option A (von Willebrand factor) is partially correct, as it plays a role in platelet adhesion to collagen. However, it is not the sole mediator of platelet adhesion.
B. Option B (glycoprotein IIb/IIIa receptor) is correct in itself, but it is not the only receptor involved in platelet adhesion to collagen.
C. Option C (glycoprotein Ib-IX-V receptor complex) is the correct answer because it encompasses both vWF and GP IIb/IIIa receptor, which together mediate platelet adhesion to collagen.
D. Option D (von Willebrand factor) is only partially correct, as it does not account for the involvement of glycoprotein receptors in platelet adhesion to collagen.
**Clinical Pearl:**
Understanding platelet adhesion and its mechanisms, including vWF and GP IIb/IIIa receptor, is essential for appreciating hemostasis and clot formation. This knowledge is crucial in clinical scenarios involving bleeding disorders or treatments affecting platelet function.