Coagulation is the process by which blood changes from a liquid to a gel, forming a blood clot. This is a crucial mechanism that helps prevent excessive bleeding when injuries occur. The process involves various proteins in the blood, known as clotting factors, which work together to create a mesh of fibrin that traps blood cells and forms a stable clot. The coagulation process can be divided into three main stages: vascular spasm, platelet plug formation, and coagulation cascade. During vascular spasm, blood vessels constrict to reduce blood flow. Platelet plug formation occurs when platelets adhere to the injury site, while the coagulation cascade activates clotting factors to strengthen the plug and form a solid clot.