Neuroregulation of the nose and bronchi.

The vascular beds, submucosal glands, and airway vasculature are the three primary effector tissues in the airways, and all are under the control of the parasympathetic (vagal) and sympathetic nervous systems. Parasympathetic nerves play a more important role in smooth muscle contraction and gland secretion. The complex neurogenic mechanisms initiated by activation of sensory nerves have been clarified to a large extent by studies on experimental animals. For example, inflammation or an allergic response will cause neurogenic inflammation due to axon reflexes; central nervous reflexes will modulate activity in all of the effector tissues; and these reflex responses will be modulated by local reflexes via parasympathetic ganglia. Similar mechanisms are suspected in humans, but their importance still needs to be fully established.