Bronchial glands and airway mucus

Bronchial glands and airway mucus constitute a critical physiological system for the protection and maintenance of the respiratory tract. The airway mucus is a complex hydrogel primarily composed of water, electrolytes, and gel-forming mucins (MUC5AC and MUC5B) secreted by surface goblet cells and submucosal bronchial glands (Fahy & Dickey, 2010). This system serves as a primary innate defense mechanism, trapping inhaled pathogens, allergens, and particulates, which are then cleared from the lungs via the mucociliary escalator (Rogers, 2007). In chronic respiratory diseases such as asthma, COPD, and cystic fibrosis, the system becomes dysfunctional, leading to mucus hypersecretion, increased viscosity, and impaired clearance, which contribute to airway obstruction and recurrent infections (Widdicombe & Wine, 2015). Pharmacological interventions include muscarinic antagonists to reduce glandular output, mucolytics to break down the mucus structure, and expectorants to enhance clearance. Understanding the regulation of these glands and the biochemical properties of mucus is essential for developing effective therapies for obstructive lung diseases.

Other names

Submucosal glandsAirway surface liquidTracheobronchial secretionsAirway mucusBronchial secretions

Drugs targeting this system act by inhibiting muscarinic M3 receptors on submucosal glands to reduce secretion volume, or by chemically/enzymatically altering mucus viscosity (e.g., via disulfide bond reduction or DNA cleavage) to facilitate clearance (Fahy & Dickey, 2010; Rogers, 2007).