• List the ways by which oxygen is carried in the blood

oxygen is carried in 2 ways towards tissues

1 (2%) oxygen is dissolved into plasma

2 (98%) oxygen is transported by haemoglobin in RBCs

• Recognise what proportion of oxgyen is carried in each form

as above

• Describe the haemoglobin oxygen dissociation curve

the oxygen-haemoglobin dissociation curve shows the cooperativity between oxygen binding to haem and the increased affinity associated leading to higher saturations

as each induvidual O2 binds (each haem can hold a total of 4) the affinity for the next to bind increases greatly per each that binds previously!

The curve is sigmoidal, with a steep slope at low partial pressures of oxygen and a more gradual slope at higher partial pressures.

• Explain the physiological significance of the shape of the curve

A rightward shift of the curve indicates that hemoglobin has a decreased affinity for oxygen, thus, oxygen actively unloads. A shift to the left indicates increased hemoglobin affinity for oxygen and an increased reluctance to release oxygen

this shift varies depending on location within the body 2 examples are explained below

Systemic capillaries

within systemic capillaries the aim for our blood is to provide oxygen for saturation of tissues therefore it would be beneficial for our haemoglobin to have a low affinity for Oxygen itself so that it can release the oxygen into the surrounding tissues. 3 things cause this to occur