The Lungs
Physical Education: AQA GCSE, topic 1.2.9
Volumes on a Spirometer Trace
A spirometer is a piece of equipment used to measure breathing volume. The reading from the spirometer is called the spirometer trace. The following volumes can be found on any given spirometer trace:
Tidal volume
- Tidal volume is the volume of air that is breathed in or out while at rest.
- The amount of air that enters the lungs is the same amount that leaves the lungs (about 500ml).
Expiratory reserve volume
- Expiratory reserve volume is the additional air that can be forced out of the lungs after 1 normal exhalation (after tidal volume).
- This is about 1000ml.
Inspiratory reserve volume
- Inspiratory reserve volume is the amount of air that can be forced into the lungs after 1 normal inhalation (after tidal volume).
- This can be as much as 3000 ml.
Residual volume
- Residual volume is the volume of air that is left in the lungs after exhalation.
- There is always some air left in the lungs (about 1500ml).
Spirometer Traces
The reading on a spirometer trace will change depending on whether it's measuring breathing during rest or exercise.
At rest
- The trace will have consistently equal peaks and troughs (highs and lows) using about 500ml of air (average person).
During exercise
- During exercise, the spirometer trace will change. The peak will increase into the inspiratory reserve volume. The trough will dip lower into the expiratory reserve volume.
- However, there is always some air left in the lungs. This prevents them from collapsing.
Test yourself on The Lungs
Which of the following is NOT a volume found on a spirometer trace?
Types of lung volume found on spirometer traces
What do we call the reading showing breathing volume made by a spirometer?
How does a spirometer trace change during exercise?
Which spirometer reading would show higher peaks and lower troughs?