Kaplan Nursing Entrance Practice Exam

What is the primary role of red blood cells?

1. Immune response

2. Gas exchange

3. Clotting

4. Transport of nutrients

The correct answer is: Gas exchange

The primary role of red blood cells (RBCs) is gas exchange, primarily the transport of oxygen from the lungs to tissues throughout the body and the return of carbon dioxide from the tissues back to the lungs for exhalation. Red blood cells contain hemoglobin, a protein that binds oxygen in the lungs and releases it as blood circulates through the body's tissues. This critical function is essential for maintaining cellular metabolism and life, as oxygen is necessary for the production of energy within cells. While red blood cells are involved in other processes to some extent, such as influencing acid-base balance, their main and most vital function is gas exchange. This distinguishes them from other components of blood, such as white blood cells, which play a role in immune response, platelets that are essential for clotting, and plasma which is responsible for transporting nutrients. Understanding the specific function of red blood cells emphasizes their crucial role in respiratory function and overall physiological health.