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Diseases of the nasal cavity and sinuses (view source)
Revision as of 21:20, 29 November 2006
, 21:20, 29 November 2006→Mucus
**Constant movement reduces chances that pathogens can adhere to the respiratory epithelium
**Constant movement reduces chances that pathogens can adhere to the respiratory epithelium
===Mucus===
===Mucus===
*Produced by the goblet cells of the respiratory epithelium and the submucosal glands with contribution from lacrimal glands draining into the nose
*Traps particles for transportation away and subsequent swallowing
*Physical barrier against mucosal damage
*Prevents dessication of the mucosal epithelium
*Contains antimicrobial substances
*Immunoglobulin - IgA
**IgA produced by mucosal plasma cells
**IgA can attach to specific pathogen antigens (viruses, bacteria) trapping them in the mucus for clearance
*Lysosyme
**Direct action on bacterial cell walls
**Lactoferrin
***Inhibits bacterial growth as sequesters iron, an essential co-factor for many bacteria
===Commensal bacteria===
===Commensal bacteria===
***The normal bacterial flora of the nasal cavity, pharynx, larynx and proximal portion of the trachea compete with potentially pathogenic bacteria and help to prevent their colonisation (competitive exclusion).
***The normal bacterial flora of the nasal cavity, pharynx, larynx and proximal portion of the trachea compete with potentially pathogenic bacteria and help to prevent their colonisation (competitive exclusion).