1. Spirometry and Breathing
f) outline the mechanism of breathing (inspiration and
expiration) in mammals, with reference to the
function of the rib cage, intercostal muscles and
diaphragm;
(g) explain the meanings of the terms tidal volume and
vital capacity;
(h) describe how a spirometer can be used to measure
vital capacity, tidal volume, breathing rate and
oxygen uptake;
(i) analyse and interpret data from a spirometer.

2. Spirometer Practical

6. Volume
Average value (litres)
Derivation
In men In women
Vital capacity 4.6 3.1
IRV plus TV plus
ERV
Inspiratory
capacity
3.8 2.4 IRV plus TV
Functional
residual
capacity
2.2 1.8 ERV plus RV
Total lung
capacity
6.0 4.2
IRV plus TV plus
ERV plus RV

7. Answers:
A - a normal healthy adult (very large vital capacity and small residual volume)
B - a small child (a small vital capacity and residual volume)
C - An elderly person with weak intercostal and abdominal muscles, or a heavy
smoker (a small vital capacity and very large residual volume)

8. Spirometry and Breathing
f) outline the mechanism of breathing (inspiration and
expiration) in mammals, with reference to the
function of the rib cage, intercostal muscles and
diaphragm;
(g) explain the meanings of the terms tidal volume and
vital capacity;
(h) describe how a spirometer can be used to measure
vital capacity, tidal volume, breathing rate and
oxygen uptake;
(i) analyse and interpret data from a spirometer.