AEMCA Practice Exam

What is the buffer layer of the blood?

1. A layer composed of erythrocytes

2. A component that contains leukocytes and platelets

3. A connective tissue structure supporting blood vessels

4. A section responsible for nutrient absorption

The correct answer is: A component that contains leukocytes and platelets

The buffer layer of the blood, often referred to in the context of a blood sample after centrifugation, primarily consists of leukocytes (white blood cells) and platelets. This layer, also known as the "buffy coat," forms a thin layer between the plasma, which is the liquid portion of the blood, and the red blood cells. The presence of leukocytes in this layer is essential as they play a critical role in the immune response and defense against infections. Platelets, on the other hand, are involved in the blood-clotting process, which is vital for wound healing and maintaining hemostasis. Thus, identifying the buffer layer as a component containing leukocytes and platelets highlights its specific role in immune function and clotting mechanisms. Other options do not accurately describe the composition of this layer. Erythrocytes, while a major component of blood, are not part of the buffer layer; they constitute the lower layer after centrifugation. Additionally, connective tissue supporting blood vessels is a separate anatomical structure and does not relate to the composition of blood layers. Likewise, nutrient absorption is a function primarily carried out by the digestive system, not by any layer of blood.