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How does coughing help remove foreign material from the trachea?

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Illustration showing different animals and their respiratory organs: a spider with book lungs, a chicken with lungs, a sponge with labeled inflow and outflow pores, a fish with gills, and a caterpillar with spiracles. — Respiratory system Different methods of respiration in animals.

Coughing is a protective reflex that serves as a critical mechanism for clearing the respiratory tract of foreign material, such as dust or irritants.1

During a cough, the muscle bands connecting the free ends of the trachea's cartilage rings contract, pressing inward to reduce the tracheal lumen to approximately one-sixth of its normal size. This forced exhalation causes air to rush through the narrowed channel at high velocities. The speed of this airflow creates the necessary force to dislodge and expel foreign elements and excessive secretions from the airway.21

This process is essential for maintaining respiratory health; when the cough reflex is impaired due to injury or disease, individuals are at a significantly higher risk of developing conditions such as pneumonia.1