Question

question 95 (0.5 points)
what is true about thrombin?
it causes platelet aggregation to the site of a wound.
it converts fibrinogen into fibrin.
it activates the intrinsic pathway of coagulation.
it activates the extrinsic pathway of coagulation.

Explanation:

To determine the correct statement about thrombin, we analyze each option:

• Platelet aggregation at a wound site is mainly caused by factors like ADP, thromboxane A₂, and collagen, not thrombin. So the first option is incorrect.
• Thrombin plays a key role in the coagulation cascade by converting fibrinogen (a soluble protein) into fibrin (an insoluble protein that forms the mesh of a blood clot). This is a core function of thrombin.
• The intrinsic pathway of coagulation is activated by factors like contact with damaged subendothelium (e.g., factor XII activation), and thrombin is a product of the coagulation cascade, not an activator of the intrinsic pathway.
• The extrinsic pathway is activated by tissue factor (factor III) released from damaged tissues, and thrombin does not activate the extrinsic pathway.

Answer:

B. It converts fibrinogen into fibrin.