The first component of blood that responds to injury is platelets, also known as thrombocytes. When a blood vessel is damaged, platelets quickly aggregate at the injury site and begin to adhere to the exposed tissue. They play a crucial role in forming a blood clot by releasing chemical signals that attract more platelets and activate the clotting cascade, which ultimately leads to the formation of fibrin—a protein that forms a mesh to stabilize the clot. This process is essential for preventing blood loss and allowing healing to occur after an injury.