Which component of blood is responsible for the repair of damaged vessels by clotting?

Platelets, also known as thrombocytes, are the component of blood that plays a crucial role in the repair of damaged blood vessels through the process of clotting. When a blood vessel is injured, platelets aggregate at the site of the injury, adhering to the exposed collagen fibers. They release chemical signals that attract more platelets to the area and initiate the coagulation cascade, leading to the formation of a fibrin mesh that solidifies the clot and helps to stop bleeding. This process, known as hemostasis, is vital for wound healing and preventing excessive blood loss.

Plasma, while it carries nutrients, hormones, and waste products, does not play a direct role in the physical process of clot formation. Red blood cells are primarily responsible for transporting oxygen throughout the body and do not have a role in clotting. White blood cells are part of the immune system and are involved in fighting infections but are not directly involved in the clotting process. Thus, it is the platelets that are essential for the initial defense against bleeding and for facilitating repair of damaged vascular tissue.