This schematic shows a revised version of the coagulation cascade that emphasizes the importance of pathways for hemostasis in vivo. Coagulation factors are shown as Roman numerals. Only the activated forms (with the suffix "a") are shown in this diagram for simplicity. Thrombin is activated factor II (factor IIa); unactivated factor II is prothrombin.
Tissue factor exposed at a wound interacts with factor VIIa and initiates clotting by two pathways:
Pathways 1 and 2 are equally important.
In a third pathway (3), thrombin also activates factor XI to factor XIa, which can lead to further generation of factor IXa; it serves as an amplification pathway required during severe hemostatic challenges.Do you want to add Medilib to your home screen?