Question
The oxygen dissociation curve of haemoglobin is sigmoid. At what partial pressure of $\text{O}_2$ is haemoglobin approximately $50\%$ saturated ($P_{50}$)?
Options
- A
$26 \text{ mmHg}$
- B
$40 \text{ mmHg}$
- C
$60 \text{ mmHg}$
- D
$100 \text{ mmHg}$