Measuring lung volumes

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Measuring lung volumes
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Syllabus reference

• outline the mechanism of breathing in mammals,
  with reference to the function of the rib cage,
  intercostal muscles and diaphragm
• explain the meanings of the terms tidal volume
  and vital capacity
• describe how a spirometer can be used to measure
  vital capacity, tidal volume, breathing rate and
  oxygen uptake
• analyse and interpret data from a spirometer

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Inspiration expiration
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Inspiration expiration
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Lung volumes
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Lung volumes

• The maximum volume of the lungs is about 5dm3 (5
  litres) although we never completely empty the
  lungs even if we breathe out as much as possible
  (expiratory capacity) there will still be about
  1.5 dm3 left in the lung (residual volume).
• The amount of air breathed in and out at each
  breath is called the tidal volume. At rest this
  will be around 0.5 dm3, rising to about 2.5 dm3
  when we are breathing very deeply.
• The maximum volume that can be exchanged by
  breathing in as much as possible and then forcing
  out as much as possible is our vital capacity.

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The spirometer
oxygen
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Spirometer
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Lung volumes
Note compare to inverted trace in textbook
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Lung volumes
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The spirometer
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Lung volumes definitions
maximum inspiration
Inspiratory capacity

Inspiratory reserve volume
Inspiratory reserve volume
Vital capacity
Vital capacity
Volume in dm3
inspiration at rest
inspiration at rest
Tidal volume
Tidal volume
Expiratory capacity
Expiratory capacity
expiration at rest
expiration at rest
Expiratory reserve volume
Expiratory reserve volume
maximum expiration
maximum expiration
Total lung capacity
Total lung capacity
Residual volume
Residual volume