[Motility of the bronchi]

Airway diameter depends on bronchial smooth muscle tone which is regulated via complex nervous influences including afferent and efferent vagal fibers, sympathetic agonists and the so called 'third nervous system' (non adrenergic non cholinergic), as recently described. Additionally, various mediators of inflammation and epithelium derived factors contribute to the regulation of bronchi motility in health and disease.