Cilia are small hairs which beat to push the mucus back up the trachea so it can be swallowed and destroyed in the stomach. Clean air then enters the two bronchi, one bronchus going to each lung.

Treating collapsing trachea in dogs can be a daunting prospect for owners. Tracheal collapse occurs when the windpipe becomes flattened and the airflow in and out of the lungs is obstructed.