Question

Look up an oxygen-hemoglobin dissociation curve. What information does it display. What would happen to folks who live at high altitudes if the line were linear instead of sigmoidal?

Answer 1

Oxygen dissociation curve is the curve that demonstrates the relationship between partial pressure of oxygen and the percentage saturation of hemoglobin with oxygen. It explains hemoglobin affinity for oxygen.

Normal shape of curve is sigmoid. Lower part of the curve indicate the dissociation of oxygen from hemoglobin. Upper part of the curve indicate the uptake of oxygen by hemoglobin.

At high altitude, the barometric pressure of oxygen is low. Due to this, the partial pressure of oxygen in atmosphere decreases. Very low Oxygen is present for the body.

So the curve obtained is linear, instead of sigmoid. It is because, since oxygen levels are very low, whatever amount of oxygen is there, it binds to hemoglobin proportionately. Hence the curve is linear.

In normal condition, since there is no problem like less oxygen, so we get sigmoid curve, because at one point of time, all the hemoglobin gets saturated with Oxygen and we get flat horizontal line.