Question

Choose the correct answer from the alternatives given.
A partial pressure gradient of oxygen exists between

• A. the atmosphere and the lungs
• B. lungs and metabolically active tissues
• C. air at sea level and air at high altitudes
• D. all of these

Answer 1

The correct option is D all of these

A difference in partial pressure helps in exchange of gases. Therefore, the partial pressure gradient of oxygen exists between the atmosphere and the alveoli of lungs, with the partial pressure in atmospheric air being higher than the partial pressure of alveolar air. A difference in partial pressure of oxygen also exists between the lungs and the metabolically active tissues, with the partial pressure in the metabolically active tissues being lower than that in the lungs. This helps oxygen to be transported from the lungs to the tissues. The partial pressure of oxygen is lower at higher altitudes in comparison to the pressure at sea level. So, the correct option is 'all of these'.