Intrinsic pathway Extrinsic pathway Blood vessel damage causes Tissue injury causes initiation f the cle initiation of the clotting ng releas ing certain bloc process proteins Vitamin K acts af Vitamin K acts at two of these steps one of these steps Prothrombin activating factor Preprothrombin Prothrombin rombin Vitamin K Fibrinogen acts at this step (soluble rin Clot formed protein) (insoluble ng ote of fibrin trap and huid