Schematic representation of the coagulation cascade including our improved understanding of the role of the tissue factor (TF) pathway in initiating clotting, interactions between pathways, and the role of thrombin in sustaining the cascade by feedback activation of coagulation factors. Factor II is prothrombin, and factor IIa is thrombin.
PK: prekallikrein; HK: high molecular weight kininogen; PL: phospholipid.