Final answer:
Hemostasis is the process of sealing a ruptured blood vessel and preventing blood loss. It involves vascular spasm, the formation of a platelet plug, and coagulation. If any of these steps fail, excessive bleeding can occur.
Step-by-step explanation:
Hemostasis is the process by which the body seals a ruptured blood vessel and prevents further loss of blood. It involves three steps: vascular spasm, the formation of a platelet plug, and coagulation (blood clotting). In vascular spasm, the smooth muscle in the walls of the damaged vessel contracts. The platelet plug is formed when platelets accumulate at the site of injury and stick together, temporarily sealing the opening. Finally, coagulation involves the formation of a clot made up of fibrin, platelets, and blood cells, which provides a more long-lasting seal. If any of these steps fail, excessive bleeding or hemorrhage can occur.