Physical Therapy Assistant Practice Exam

What is the function of hemoglobin in red blood cells?

1. Transport of nutrients

2. Regulation of blood pressure

3. Transport of oxygen

4. Production of red blood cells

The correct answer is: Transport of oxygen

Hemoglobin's primary function within red blood cells is the transport of oxygen from the lungs to the tissues throughout the body. Each hemoglobin molecule can bind up to four oxygen molecules, facilitating their delivery. The presence of hemoglobin allows red blood cells to effectively carry oxygen due to its high affinity for oxygen in the lungs, where oxygen concentration is high. Once the red blood cells reach the tissues, hemoglobin releases the oxygen, enabling it to diffuse into cells where it is used for metabolic processes, particularly respiration. In addition to oxygen transport, hemoglobin also plays a role in the transport of carbon dioxide, the waste product of metabolism, back to the lungs, where it can be exhaled. However, its primary and most significant role remains the transport of oxygen, ensuring that all body systems receive the necessary oxygen to function optimally.