Airway

From Wikinfo

The airways are those parts of the respiratory system through which air flows between the external environment and the alveoli.

Protection of the airways

1. The epithelial surfaces of the airways contain cilia. Particles such as dust sticks to mucous which is continuously removed from the airways by these cilia. The airway epithelium also secretes a watery fluid upon which the mucous can ride freely. The production of this fluid is impaired by the disease cystic fibrosis.
2. Macrophages are present in the airways. These cells protect the airways from infection by engulfing inhaled particles and bacteria.

References

• Adapted from the Wikipedia article, "Airway" http://en.wikipedia.org/wiki/Airway, used under the GNU Free Documentation License