F3 (Factor III)

Factor III, also known as Tissue Factor or thromboplastin, is a protein found in tissues outside the blood vessels. It plays a crucial role in blood clotting by activating the body's clotting cascade when there's an injury. When a blood vessel is injured, Factor III is exposed to blood, triggering a series of reactions that form a clot to stop bleeding. Essentially, it acts as the initial signal that helps the body respond to injury and prevent excessive blood loss, making it vital for proper wound healing and maintaining blood stability.