What primarily activates the intrinsic pathway of coagulation?

What primarily activates the intrinsic pathway of coagulation?

• A. External trauma
• B. Damage to blood vessels
• C. Platelet aggregation
• D. Thrombin generation

Answer: (B)

The intrinsic pathway of coagulation is primarily activated by damage to blood vessels. This pathway is a critical component of the coagulation cascade, which is essential for hemostasis (the prevention of excessive bleeding). When blood vessels are injured, exposed collagen and other subendothelial structures trigger the intrinsic pathway. This process begins when factor XII (Hageman factor) interacts with negatively charged surfaces, which can include the exposed collagen fibers. The activation of factor XII leads to a cascade of reactions involving several other clotting factors, ultimately leading to the conversion of prothrombin to thrombin and the formation of fibrin, which stabilizes the clot. Thus, the intrinsic pathway is specifically designed to respond to internal vascular injury, making it crucial for the body's hemostatic response. In contrast, external trauma would fall under the extrinsic pathway, which is activated by tissue factor released from damaged cells outside the vascular system, while platelet aggregation and thrombin generation are outcomes within the coagulation process rather than initial activators of the intrinsic pathway.

The intrinsic pathway of coagulation is primarily activated by damage to blood vessels. This pathway is a critical component of the coagulation cascade, which is essential for hemostasis (the prevention of excessive bleeding). When blood vessels are injured, exposed collagen and other subendothelial structures trigger the intrinsic pathway. This process begins when factor XII (Hageman factor) interacts with negatively charged surfaces, which can include the exposed collagen fibers.

The activation of factor XII leads to a cascade of reactions involving several other clotting factors, ultimately leading to the conversion of prothrombin to thrombin and the formation of fibrin, which stabilizes the clot. Thus, the intrinsic pathway is specifically designed to respond to internal vascular injury, making it crucial for the body's hemostatic response. In contrast, external trauma would fall under the extrinsic pathway, which is activated by tissue factor released from damaged cells outside the vascular system, while platelet aggregation and thrombin generation are outcomes within the coagulation process rather than initial activators of the intrinsic pathway.