The nasal hairs and cilia trap particles that enter via inhaled air during breathing to protect the respiratory system.

The nasal cavity contains hair in the lining that helps to filter the foreign particles that come in through the inhaled air. The nasal hairs push them back outwards and avoid their entry in the trachea.

The lining of the respiratory tract also has mucus, which is secreted by goblet cells. This traps foreign particles from the inhaled air. The lining of the trachea and bronchi also have hair-like cilia that move forwards and backwards. This helps to push the foreign particles outwards just like the nasal hair.

Key Points

• The nasal hair pushes the foreign particle from the inhaled air outside the nasal cavity. Cilia do this in the further parts of the respiratory tract.

• The mucus in the lining of the respiratory tract traps the foreign particulate matter.

Key Terms

mucus: sticky fluid present in the lining of the respiratory tract

cilia: mobile hair-like projections

trachea: tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung

nasal cavity: an ample, air-filled space above and behind the nose in the middle of the face