What accounts for the change in PO₂ between the atmosphere and alveoli?
I.Water vapor pressure in alveolar gas
II.PCO₂ is higher in alveolus than in the atmospheric gas
III.Higher percentage of N₂ in alveolar gas
IV.PB is lower in the alveoli than in the atmosphere
A) I and II only
B) I, II, III, and IV
C) I and IVonly
D) I, II and IV only

Question

Quizplus · Accepted Answer

The change in PO₂ between the atmosphere and alveoli is accounted for by the water vapor pressure in alveolar gas, which decreases the partial pressure of oxygen, and the fact that PCO₂ is higher in the alveolus than in atmospheric gas, which also displaces oxygen.

What Accounts for the Change in PO₂ Between the Atmosphere