What initiates the common pathway in the coagulation process?

The common pathway in the coagulation process is initiated by Factor 10, also known as Stuart-Prower factor. Upon activation, Factor 10 plays a critical role in the coagulation cascade by converting prothrombin (Factor 2) into thrombin, which is essential for the subsequent formation of fibrin and the stabilization of the blood clot.

This pathway is central to hemostasis, as it links the intrinsic and extrinsic pathways of the coagulation cascade, leading to the final formation of a stable fibrin clot. The activation of Factor 10 can be initiated by either the prothrombinase complex formed by Factor 5 and Factor 10 in the presence of calcium ions or directly by Factor 7 in the extrinsic pathway. The transition to the common pathway signifies the final steps in the coagulation process, highlighting the importance of Factor 10 in ensuring effective and timely clot formation.

Factors such as 5, 3, and 1 serve important roles at different stages of the coagulation process, but it is Factor 10 that specifically initiates the common pathway.