Briefly describe the factors that affect lung compliance.

[Click here to toggle visibility of the answers]

College Answer

Main points/concepts expected in answer.

  • Surfactant • increases lung compliance • decreases surface tension at alveolar air -water- interface •prevents small alveoli from collapsing •accounts for most of hysteresis in intact lung
  • Lung elastic recoil • lung compliance changes in disease states
  • Lung volume • lung compliance greatest around FRC • lung compliance reduced at low and high lung volumes • gravitational effects on regional lung compliance
  • Pulmonary blood volume • pulmonary venous congestion reduces lung compliance
  • Lung size • specific compliance = lung compliance I PRC
  • Dynamic lung compliance • influenced by airways resistance • lung compliance measured during normal breathing • less than static lung compliance • frequency dependence