Which factor is the first in the common pathway of coagulation?

The common pathway of coagulation is initiated once both the intrinsic and extrinsic pathways converge and lead to the activation of Factor 10, also known as Stuart-Prower factor. This is a pivotal point in the coagulation cascade because Factor 10, once activated to Factor 10a, acts as a key enzyme that catalyzes the conversion of prothrombin into thrombin, ultimately leading to the formation of fibrin and the stabilization of the blood clot.

Understanding the role of Factor 10 in the coagulation process is crucial, as it serves as a bridge linking both the extrinsic and intrinsic pathways, making it essential for effective hemostasis. Thus, within the context of the common pathway, Factor 10 is the first factor activated and is central to the process of clot formation.