Using the spirometer

• how can the spirometer be used to measure lung volume?

  • CO2 is filtered out using soda lime, meaning the total volume will slowly decrease
  • it can be used to measure the rate of oxygen uptake
• what is the total lung capacity?

  volume of air in the lungs after maximal inspiration
• what is the tidal volume?

  volume of air moved in and out of the lungs with each breath at rest
• what is the vital capacity?

  largest volume of air that can be moved into and out of the lungs in any one breath
• what is the residual volume?

  volume of air that always remains in the lungs, even after the biggest possible exhalation - always replaced (ventilation)
• what is dead space?

  amount of air in the bronchioles, bronchi and trachea (not exchange surfaces)
• what is the inspiration reserve volume?

  how much more air can be breathed in (inspired) over and above the normal tidal volume when you take a big breath
• what is the expiratory reserve volume?

  how much more air can be breathed out (expired) above the tidal volume
• what is the equation and units for breathing rate?

  No. breaths * 60

  —————————-

  time in seconds

  • breaths per minute
• what is the equation and units for tidal volume?

  • difference from the peak to the trough of a breath (even better if you work out the mean from all breaths)
  • dm3
• what is the equation and units for rate of oxygen uptake?

  volume difference between peaks * 60

  ——————————————————

  difference in time in seconds

  • dm3/min
• label the diagram

  A) total lung capacity

  B) vital capacity

  C) tidal volume

  D) functional residual volume

  E) residual volume

  F) pen

  G) breathing out makes pen move in opposite direction

  H) breathing in removes oxygen from chamber, so pen moves

  I) spirometer

  J) oxygen-filled chamber floating on a tank of water

  
• label the diagram

  A) inspiratory reserve volume

  B) tidal volume

  C) functional residual capacity

  D) residual volume

  E) expiratory reserve volume

  F) inspiratory capacity

  G) vital capacity

  H) total lung capacity