Blood coagulation is the process by which blood changes from a liquid to a gel, forming a blood clot. This is essential for stopping bleeding when a blood vessel is injured. The process involves a series of proteins in the blood, known as clotting factors, which work together to form a stable clot. When a blood vessel is damaged, platelets, a type of blood cell, quickly gather at the injury site. They release chemicals that activate the clotting factors, leading to a cascade of reactions. This results in the formation of fibrin, a protein that weaves through the platelets, creating a mesh that solidifies the clot and helps seal the wound.