What are the two types of clots that can form?

* Thrombus: A thrombus is a clot that forms inside a blood vessel. Thrombi can be either red or white. Red thrombi are composed of fibrin, platelets, and red blood cells. White thrombi are composed of fibrin, platelets, and white blood cells.

* Embolus: An embolus is a clot that has broken off from a thrombus and is circulating in the bloodstream. Emboli can travel to different parts of the body and block blood flow, causing ischemia.