Module 3: Oxygen Uptake in Mammals
These free OCR A Level Biology Oxygen Uptake in Mammals revision notes have been written for specification point 3.1.1(e).
Oxygen Uptake
Oxygen uptake is the rate at which oxygen moves into the bloodstream (in mammals) per minute.
The rate of oxygen uptake is affected by the effectiveness of pulmonary ventilation.
It can be measured as the volume of air breathed per minute, calculated as:
Tidal Volume × Breathing Rate
Where:
- Tidal volume is the volume of air inhaled or exhaled in a breath at rest
- Breathing rate is the number of breaths per minute
Tidal volume is affected by the lung’s vital capacity, a key indicator of respiratory health.
Vital capacity is the maximum volume of air that can be inhaled and exhaled during a forced breath.
So, oxygen uptake can increase if:
- Tidal volume increases (deeper breaths)
- Breathing rate increases (more breaths per minute)
Vital capacity is a fixed maximum and only changes with lung health and fitness.
Residual volume is the volume of air that remains in the lungs after forced exhalation.
The diagram below shows how these factors affect each other:
