Airway submucosal glands produce the mucus that lines the upper airways to protect them
against insults. This review summarizes evidence for two forms of gland secretion, and
hypothesizes that each is mediated by different but partially overlapping neural pathways.
Airway innate defense comprises low level gland secretion, mucociliary clearance and
surveillance by airway-resident phagocytes to keep the airways sterile in spite of nearly
continuous inhalation of low levels of pathogens. Gland secretion serving innate defense is …