Gas exchange

• What is the primary function of alveoli in the lungs?

  Gas exchange
• How does the structure of alveoli aid their function?

  Alveoli have thin walls that are one cell thick, providing a short diffusion pathway
• What is the definition of external respiration?

  • Exchange of gases between the lungs and blood
• What is the definition of internal respiration?

  • Exchange of gases between blood and muscles
• What is tidal volume?

  The volume of air inspired per breath
• What is minute ventilation?

  The volume of air inspired or expired per minute
• Why is the resting minute ventilation of an aerobic athlete lower than that of an untrained athlete?

  Because gas exchange at their alveoli is more efficient, leading to increased oxyhaemoglobin saturation
• What happens to breathing frequency during submaximal exercise?

  • Increases until it plateaus at a level that meets oxygen demand
• What happens to tidal volume during maximal exercise?

  • Continues to increase to approximately 3.5L
• What is the approximate resting minute ventilation for a trained athlete?

  Approximately 6 L/min
• What is the typical minute ventilation during exercise for untrained individuals?

  Can rise to approximately 160 L/min
• Describe the response of minute ventilation to exercise.

  • Submaximal: Increases as exercise intensity increases
  • Maximal: Rapid rise to a plateau as supply meets demand
• How does the breathing frequency change from resting to maximal exercise?

  It increases from approximately 12 breaths/min to 60 breaths/min
• What is the heart rate value equivalent of minute ventilation?

  It varies based on exercise intensity and individual fitness levels
• What is the role of anticipatory rise in minute ventilation during exercise?

  It raises minute ventilation due to excitement and nerves before exercise starts
• What is the recovery response of minute ventilation after exercise?

  • Rapid decline followed by a much slower decrease to resting value