Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What process is primarily carried out by platelets in the blood?

1. Oxygen transport

2. Immune response

3. Blood clotting

4. Nutrient transport

The correct answer is: Blood clotting

The process primarily carried out by platelets in the blood is blood clotting. Platelets, or thrombocytes, play a critical role in hemostasis, which is the process that prevents and stops bleeding. When a blood vessel is injured, platelets are activated and aggregate at the site of the injury, forming a temporary "platelet plug." They release various chemicals that help recruit more platelets to the area, as well as promoting the cascade of reactions that ultimately leads to the formation of fibrin, a protein that stabilizes the clot. This entire process ensures that blood loss is minimized while the tissue begins to heal. In contrast, the other processes mentioned are performed by different blood components. Oxygen transport is primarily the function of red blood cells, which contain hemoglobin to bind and carry oxygen from the lungs to the tissues. The immune response involves white blood cells, which are responsible for fighting infections and protecting the body against foreign substances. Nutrient transport is carried out by plasma and other components in the blood, which carry nutrients needed by various tissues throughout the body. Thus, platelets are specifically essential for the blood clotting mechanism.