Mucus

Hairs in the nose trap some of these particles, while sticky mucus traps pathogens before they travel farther into the breathing system.

Mucus in the nose and airways is sticky, so it traps them. Cells lining the trachea and bronchi have cilia—tiny hair-like structures that beat to move the mucus towards the throat. The mucus can then be coughed out or swallowed.

Nose hairs and sticky mucus help trap them. The trachea and bronchi also produce mucus, which traps pathogens that reach the airways. Tiny cilia on the airway lining beat to move this mucus upwards towards the back of the throat, where it can be swallowed.

The nose contains hairs and sticky mucus, which trap pathogens and other particles in inhaled air. Cells lining the trachea and bronchi also produce mucus. Their cilia beat to move the pathogen-containing mucus upwards towards the throat, where it can be swallowed rather than reaching deeper into the lungs.