In the average adult, approximately 150 mL of the air that is inhaled with each breath never reaches the alveoli. It fills the nose, mouth, larynx, trachea, bronchi, and bronchioles, a volume known as the “dead space.” This air is not available for gas mixing and exchange. It mixes with newly inhaled air and is “recycled” back to the alveoli. The relative size of the “dead space” as compared to functioning lung tissue impacts the efficiency of the respiratory system. Dead space is important in a variety of medical conditions such as asthma, pneumonia, and emphysema, and must be considered in treatments such as artificial ventilation in an intensive care unit. It is also important in physiologic challenges such as diving and high altitude activities.


In this experiment, you will

  • Simulate different volumes of dead space.
  • Measure the oxygen concentration within the dead space.
  • Correlate dead space volume with a variety of physiologic challenges.