The airplane you are riding suddenly depressurizes at 10,000 feet in the air. This causes the PO₂ of the airplane's air to drastically decrease. You pass out before you can put on your oxygen mask. After a few seconds, the PO₂ in your alveoli rapidly drops to 60 mmHg instead of the normal 104 mmHg. How will this affect blood gas concentrations?

Question

Quizplus · Accepted Answer

When the PO₂ in the alveoli drops to 60 mmHg, there is not enough oxygen flowing into the bloodstream to adequately oxygenate the body's tissues. This results in low blood PO₂, which means less oxygen is being delivered to the tissues. The higher blood PCO₂ is not a direct result of the decreased PO₂, but rather a consequence of the body's attempt to compensate for the low oxygen levels by increasing breathing rate and depth, which leads to more CO₂ being exhaled. The other options are not accurate because while there may be some diffusion of oxygen out of hemoglobin in the alveoli (option A), it would not cause blood oxygen concentrations to drop throughout the body, and it is still possible for gas exchange to occur at a PO₂ of 60 mmHg (option D).

The Airplane You Are Riding Suddenly Depressurizes at 10,000 Feet