<prompt> Thrombomodulin-thrombin complex prevents clotting becauseThrombomodulin inhibits prothrombin activatorThrombomodulin-thrombin complex activities anti-thrombin IIIThe binding of thrombomodulin with thrombin removes thrombin and also activities a plasma protein C which inactivates activated factors V VIIIThrombomodulin-thrombin complex activates heparin  <response>: The endothelium of the blood vessels also plays an active role in preventing the extension of clots. All endothelial cells except those in the cerebral microcirculation produce thrombomodulin, a thrombin-binding protein, on their surfaces. In circulating blood, thrombin is a procoagulant that activates factors V and VIII, but when it binds to thrombomodulin, it becomes an anticoagulant in that the thrombomodulin-thrombin complex activates protein C. Activated protein C APC, along with its cofactor protein S, inactivates factors V and VIII and inactivates an inhibitor of tissue plasminogen activator, increasing the formation of plasmin.Ref: Ganong;s Review of medical physiology 25th edition. Page: 565 