The partial pressure of oxygen
A)in the atmospheric air averages 79 percent of total atmospheric pressure
B)in blood is the most important factor that determines percent O₂ saturation of Hb
C)in arterial blood decreases when Hb preferentially combines with CO rather than O₂
D)is both b and c
E)is none of the above

Question

Quizplus · Accepted Answer

The partial pressure of oxygen in blood is the most important factor that determines the percent O2 saturation of Hb. Hemoglobin (Hb) combines with oxygen (O2) in the lungs and releases it in the tissues, but this process is dependent on the partial pressure of oxygen. When the partial pressure of oxygen is high, Hb binds more O2, and when it is low, Hb releases O2. Therefore, the partial pressure of oxygen in blood is the main driver of the oxygen-carrying capacity of hemoglobin. None of the other answer choices are correct.

The Partial Pressure of Oxygen