Following injury to a blood vessel, activated platelets aggregate around the site of the injury.
Factor VIII circulating in the blood in a complex with von Willebrand factor is activated by locally generated thrombin.
On the surface of the activated platelets, activated FVIII forms the tenase complex with activated factor nine (IX). This complex activates factor ten (X).
The activated Factor X then forms the prothrombinase complex with activated factor V. This complex rapidly generates thrombin from pro-thrombin creating the so-called thrombin burst