What term describes blood flow past alveoli?

• A. Diffusion
• B. Ventilation
• C. Perfusion
• D. Circular flow

Answer: (C)

The correct term that describes blood flow past the alveoli is perfusion. Perfusion refers specifically to the process by which blood circulates through the pulmonary capillaries surrounding the alveoli, allowing for the exchange of gases (oxygen and carbon dioxide) between the blood and the air in the alveoli. This is a critical component of the respiratory system, as effective perfusion is necessary for proper gas exchange to occur.

In contrast, diffusion relates to the movement of gases across membranes and involves the transfer of oxygen from the alveoli into the blood and the transfer of carbon dioxide from the blood into the alveoli. Ventilation refers to the process of moving air in and out of the lungs, which is essential for ensuring that the alveoli are filled with fresh air for gas exchange. Circular flow does not accurately describe any specific physiological process related to the blood flow around the alveoli. Thus, perfusion is the most accurate and appropriate term for blood flow past the alveoli.