What role do thrombocytes play in the blood?

Thrombocytes, also known as platelets, play a crucial role in the process of blood clotting, which is essential for hemostasis—the prevention of excessive bleeding when the vascular system is injured. When a blood vessel is damaged, thrombocytes are activated and aggregate at the site of the injury. They adhere to the exposed collagen and other components of the vessel wall and release various substances that help recruit even more platelets to form a stable clot. This clot serves as a barrier to blood loss and provides a framework for tissue repair.

While the other options relate to different functions within the circulatory system, they do not pertain to the primary role of thrombocytes. For example, the transport of nutrients is mainly performed by red blood cells and plasma components. Cellular respiration is a metabolic process carried out by cells, utilizing oxygen and glucose to produce energy, and is not directly related to the function of thrombocytes. Defense against pathogens is primarily the role of white blood cells, which are responsible for the immune response. Thus, thrombocytes are specifically designated for blood clotting.