In which condition does a blood clot form in the circulatory system?

Thrombocytes or platelets are the blood cells, whose function is to stop bleeding.

Thrombosis is a condition in which there is a formation of a blood clot inside a blood vessel. This obstructs the flow of blood through the circulatory system. Thrombin is the enzyme that converts fibrinogen to fibrin which leads to the formation of a fibrin clot.