Oxygen is carried in the red blood cells attached to haemoglobin molecules.
The oxygen saturation is a measure of how much oxygen the haemoglobin is carrying.
Question: Why is arterial blood bright red and venous blood dark red?
Scanning Electron Micrograph (SEM) of Red Blood Cells
Oxygen is carried in the red blood cells attached to haemoglobin molecules.
The oxygen saturation is a measure of how much oxygen the haemoglobin is carrying.
Question: Why is arterial blood bright red and venous blood dark red?
Answer: The colour of blood depends how much haemoglobin is saturated with oxygen:
- Arterial blood is fully saturated with oxygen and is bright red
- Venous blood has less oxygen and is dark red
Scanning Electron Micrograph (SEM) of Red Blood Cells