3.2.12 Adult & Fetal Haemoglobin Flashcards
The Oxygen Dissociation Curve
The oxygen dissociation curve shows the rate at which oxygen associates and also dissociates, withy haemoglobin at different partial pressures of oxygen (pO2)
- partials pressure of oxygen refers to the pressure extorted by oxygen within a mixture of gases; it is a measure of oxygen concentration
- haemoglobin is referred to as being saturated when all of its oxygen binding sites are taken up with oxygen; so when it contains 4 oxygen molecules
The ease with which haemoglobin binds and dissociates with oxygen can be described as its affinity for oxygen
- when haemoglobin has a high affinity, it binds easily and dissociates slowly
- when haemoglobin has a low affinity for oxygen, it bind slowly and dissociates easily
In other liquids, such as water, we would expect oxygen to become associated with water, or to dissolve, as a constant rate, providing a straight line on a graph, but with haemoglobin, oxygen binds at different rates as the pO2 changes, hence the resulting curve
- it can be said that haemoglobin’s affinity for oxygen changes at different partial pressures of oxygen
Explaining the Shape of the Curve
use with the corresponding paper flashcard
The curve shape of the oxygen dissociation curve for haemoglobin can be explained as follows:
