Airway protection 



Effects of Lost Nasal Functions

The functions of the nose that are of importance for respiration are filtering and conditioning air during inspiration, preserving heat and water loss during expiration and its air flow resistance. The nose is an effective filter for particles larger than 30 mm. These particles are deposited in the mucus covering the nasal epithelium and are transported towards the hypopharynx. The nose and nasopharynx are also effective in increasing the water content and temperature of inspired air. This conditioning is necessary to maintain a healthy mucosa of the tracheobroncheal tree.

The mucosal lining of the tracheobroncheal tree consists of secreting and ciliated epithelial cells that transports mucus to the hypopharynx. This epithelial lining is covered by a mucus layer which is produced by the secreting cells. The mucus is transported to the hypopharynx. It consists of two layers: the upper viscous gel layer which is transported along the tips of the cilia and a watery, low viscosity sol layer which surrounds the cilia.67

Alteration of the mucus layer, especially the sol layer will decrease the ciliary beat and thereby the escalator transport function towards the hypopharynx. The constitution of the mucus layer can be affected by systemic hydration and by air humidification and air heating.

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Copyright 1998 Medical Illustrations
Last modified: January 07, 1999

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