Under normal conditions at sea level,the partial pressure of oxygen in the alveoli region of the lung is
A)760 mmHg.
B)159 mmHg.
C)125 mmHg.
D)100 mmHg.

Question

Quizplus · Accepted Answer

Under normal conditions at sea level, the partial pressure of oxygen in the alveoli region of the lung is approximately 100 mmHg. This is because the atmospheric pressure at sea level is 760 mmHg and the fractional concentration of oxygen in inspired air is approximately 0.21. Therefore, the partial pressure of oxygen in inspired air is 0.21 x 760 = 160 mmHg. However, some of this oxygen is absorbed by the tissues of the respiratory tract and does not reach the alveoli, resulting in a slightly lower partial pressure of oxygen in the alveoli region of the lung.

Under Normal Conditions at Sea Level,the Partial Pressure of Oxygen