For Maximum Loading of Hemoglobin with Oxygen at the Lungs

Question

For maximum loading of hemoglobin with oxygen at the lungs, the
A) PCO2 should be high.
B) pH should be slightly acidic.
C) PO2 should be about 70 mm Hg.
D) BPG levels in the red blood cells should be high.
E) PO2 should be as high as possible.

Accepted Answer

Hemoglobin's affinity for oxygen increases with increasing PO2, so a high PO2 is needed for maximum loading of hemoglobin with oxygen at the lungs. Choices A and B are incorrect because high PCO2 and acidic pH would cause hemoglobin to release oxygen, not load it. Choice C is incorrect because a PO2 of 70 mm Hg would result in incomplete loading of hemoglobin with oxygen. Choice D is also incorrect because high levels of BPG in the red blood cells decrease hemoglobin's affinity for oxygen, resulting in more oxygen being released from hemoglobin rather than loaded.