Final answer:
Factor XIII is the substance incorporated in clot development that is activated by tPA, thrombin, or factor XII. It stabilizes the fibrin clot, playing a vital role in the blood clotting process and the subsequent step of fibrinolysis, the breakdown of the clot.
Step-by-step explanation:
Factor XIII is strategically incorporated in developing clot and is activated by tPA (tissue plasminogen activator), thrombin or XII. In the common pathway, both the intrinsic and extrinsic pathways lead to the production of fibrin to seal off the vessel. Factor XIII plays a critical role in this process as it stabilizes the fibrin clot and slows fibrinolysis, which is the gradual degradation of the clot.
When factor X is activated by the intrinsic or extrinsic pathway, prothrombinase converts prothrombin into the active enzyme thrombin. Thrombin then turns fibrinogen into fibrin protein strands. Thanks to factor XIII, these strands are stabilized, which ensures that the clot remains intact until the vessel can be properly sealed and healed.
Fibrinolysis involves the breakdown of the fibrin clot, which is essential for restoring normal blood flow as the vessel heals. The intrinsic pathway can activate factor XIII and initiate this process, which is catalyzed by tissue plasminogen activator converting the inactive plasminogen into plasmin, the main enzyme that breaks down clots.