ventilation in mammals

• Explain how a spirometer works?

  Used to measure lung volume and investigate breathing.

  • The spirometer has an oxygen-filled chamber with a moveable lid.
  • The person breathes through a tube connected to the oxygen chamber.
  • As the person breathes in and out, the lid of the chamber moves up and down.
  • These movements can be recorded by a pen attached to the lid of the chamber, this writes on a rotating drum, creating a spirometer trace. Showing the volume of breaths.
  • The soda lime in the tube the subject breathes into absorbs carbon dioxide.
• What is the definition of vital capacity?

  The maximum volume of air that an individual can inhale and exhale during a deep breath.

  Can be calculated from the spirometer graph by finding the maximum amplitude.
• What is the definition of tidal volume?

  The volume of air we breathe in and out during each breath at rest.

  Can be calculated from the spirometer graph by finding the amplitude at rest.
• What is the definition of breathing rate?

  The number of breaths we take per minute.

  Can be calculated from the spirometer graph by counting the number of peaks in one minute.
• What is the equation for ventilation rate?

  Ventilation rate = tidal volume x breathing rate
• When will oxygen uptake increase?

  When the ventilation rate increases e.g during excercise.