Question

What is hysteresis in the lungs?

Answer 1

Lung hysteresis

1. Hysteresis in the lungs occurs when at the given pressure the volume of the lungs during the inspiration process is less than the lung volume during the expiration process.
2. This occurs due to the following factors-
   1. Surfactant's effect,
   2. The extent of lung tissue relaxation,
   3. Decrecruitment and recruitment of alveoli,
   4. Gas absorption,
   5. The difference in inspiratory and expiratory volume.
3. This indicates the pressure needed for inspiration is more than the pressure required for expiration.