The inside of the |lungs|, from the bronchii to the |alveoli|, is layered with a ~mucous~ lining. This lining helps to lubricate the |lungs|, keeping them moist so that respiration doesn't dry them out, and for trapping particulates such as dust, smoke, and other debris so that it can be coughed out or pushed out by |cilia|. |Cilia| are tiny hairs which cover the inside of many ~mucous~ linings. They are found throughout the body and, by their wave-like motion, they serve to filter and transport particulate material along the surface of the mucosal lining. Respiratory |cilia| are responsible for helping to filter dust and debris out of inhaled ~air~ and transmitting it with ~mucous~ to the |pharynx| to be swallowed. The |nasal cavity|, |pharynx|, |trachea|, and bronchii ~mucous~ linings all have these structures.
