Middle (Tracheobronchial)
- Trachea (windpipe), bronchi.
- Rings of cartilage and muscle.
. Cartilage provides structural support.
. Muscles contract to help force air.
= Coughing, sneezing.
- Lined with mucous membrane and hairs (cilia).
. Cilia move like waves to push mucus and particles upward.
. Cigarette smoking can paralyze the cilia.
. Particle-laden mucus is removed by coughing, expectorating, or swallowing.