Milady Esthetics State Board Practice Test

Which part of the blood is primarily responsible for clotting?

1. Red blood cells

2. Plasma

3. Platelets

4. White blood cells

The correct answer is: Platelets

The part of the blood primarily responsible for clotting is platelets. Platelets, or thrombocytes, are small, disc-shaped cell fragments that play a crucial role in the coagulation process. When a blood vessel is injured, platelets quickly adhere to the site of the injury and to each other, forming a temporary "platelet plug" to help stem bleeding. They release chemical signals that invite more platelets to the area and activate the coagulation cascade, leading to the formation of a stable blood clot. While red blood cells are involved in transporting oxygen, plasma serves as the liquid medium for cells and contains proteins that can assist in various functions including immunity and nutrient transport, and white blood cells are primarily involved in immune responses, they do not play a direct role in the clotting process. Thus, the primary function of platelets is vital for effectively preventing excessive blood loss after injury.