Question

For maximum loading of hemoglobin with oxygen at the lungs, the

a)PO2 should be about 70 mm Hg.

b) pH should be slightly acidic.

c) BPG levels in the red blood cells should be high.

d) PCO2 should be high.

e) PO2 should be as high as possible.

Answer 1

E) PO2 should be as high as possible because as partial pressure of oxygen increases,the number of oxygen molecules bound by haemoglobin increases , thereby increasing saturation of haemoglobin.

The rest of the options decease the oxygen loading . Normal Po2 before loading is 40 mmHg and after oxygenation is 100 mm Hg while PO2 in alveoli is 105mm Hg

Acidic pH dcreases oxygen affinity for haemoglobin .

2,3 BPG levels increase in blood leads to decrease in affinity of haemoglobin for oxygen .

Similarly high pco2 decreases affinity of haemoglobin for oxygen .