Final answer:
During the common pathway, fibrinogen is converted to fibrin.
Step-by-step explanation:
The conversion of fibrinogen to fibrin occurs during the final step of the common pathway in blood clotting.
- First, factor X is activated by either the intrinsic or extrinsic pathway.
- Next, the enzyme prothrombinase converts factor II, the inactive enzyme prothrombin, into the active enzyme thrombin.
- Finally, thrombin converts factor I, the soluble fibrinogen, into the insoluble fibrin protein strands.
- Factor XIII then stabilizes the fibrin clot.
These fibrin strands form the basis of a blood clot, providing a mesh that traps platelets and erythrocytes to seal off the vessel. Afterwards, Factor XIII works to stabilize the emerging fibrin clot, securing the structure and ensuring its effectiveness.