In an environment with low ambient oxygen but adequate ventilation, which process may continue despite low oxygenation?

• A. Oxygenation continues
• B. Ventilation may continue despite adequate oxygenation
• C. Both stop
• D. Oxygenation stops but ventilation continues

Answer: (B)

Ventilation and oxygenation are two different parts of breathing: ventilation is the physical movement of air in and out of the lungs, while oxygenation is the transfer of oxygen from the alveoli into the blood. In an environment with low ambient oxygen, but with good ventilation, the lungs can still move air effectively. That means ventilation may continue even though the oxygen content of the air and the resulting oxygenation of the blood are reduced. Oxygenation depends on having enough oxygen in the inspired air and on the diffusion of that oxygen into the blood; when ambient oxygen is low, oxygenation can fall even if breathing continues normally. So the process that can persist under these conditions is ventilation.