What role do red blood cells (erythrocytes) play in respiration?

• A. They transport oxygen and some carbon dioxide in the blood primarily via hemoglobin binding.
• B. They carry out most ATP production for the body through mitochondrial oxidative phosphorylation.
• C. They produce pulmonary surfactant to reduce surface tension in the alveoli.
• D. They release neurotransmitters that directly regulate the rate of breathing in the brainstem.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the primary function of red blood cells (erythrocytes) in the context of respiration. Red blood cells are specialized cells in the blood responsible for transporting gases between the lungs and body tissues.
2. Step 2: Recognize that red blood cells contain hemoglobin, a protein that binds oxygen molecules in the lungs and carries them through the bloodstream to tissues where oxygen is needed.
3. Step 3: Note that red blood cells also assist in transporting some carbon dioxide, a waste product of cellular respiration, from the tissues back to the lungs for exhalation, primarily by binding it to hemoglobin or converting it to bicarbonate.
4. Step 4: Differentiate the roles of other options: ATP production occurs in mitochondria of body cells, pulmonary surfactant is produced by alveolar cells in the lungs, and neurotransmitter release regulating breathing is a function of neurons in the brainstem, not red blood cells.
5. Step 5: Conclude that the key role of red blood cells in respiration is the transport of oxygen and some carbon dioxide via hemoglobin binding, facilitating gas exchange essential for cellular metabolism.