Question

Explain how oxygen dissociation curve shifts affect oxygen loading in the lungs and unloading at the tissues.

Answer 1

As blood flows through the lungs, oxygen is loaded onto hemoglobin, and that forms what we call oxyhemoglobin. As blood flows through the metabolizing tissues, oxygen is unloaded from the oxyhemoglobin, forming what we call deoxyhemoglobin.

A rightward shift of the curve indicates that hemoglobin has decreased affinity for oxygen this will make it more difficulty for hemoglobin to bind it to oxygen, but it will make it easier for hemoglobin to release oxygen bound to it, this means more oxygen is released into the tissues, which is what required.

A leftward shift indicates that hemoglobin has increased affinity for oxygen, so that hemoglobin readily binds to oxygen, but unloads it more reluctantly, this is favoured in the lungs which allows it to carry more oxygen molecules.

Increase in body temperature, increase in pCO2, increase in 2,3 BPG, decrease in pH shifts the curve to the right and vice-versa.