During a laboratory exercise on coagulation testing, a 23-year-old medical student is found to have a prolonged bleeding time. She has had a long history of "easy bleeding," with frequent bleeding of the gums, epistaxis, cutaneous bleeding, and menorrhagia. Fuher testing revealed a deficiency of Von Willebrand factor. Which of the following thrombogenic processes involving platelets is most directly impaired?
High-Yield Explanation
Disruption of the endothelium exposes subendothelial von Willebrand factor (vWF) and collagen, which promote platelet adherence and activation. Deficiency of Von willebrand factor (VWF) causes | platelet adhesion ( |BT) and | Intrinsic pathway activity ( | aPTT) .