Pulmonary plexus

Pulmonary plexus is an interconnected meshwork of neurons which is situated around the bifurcation of trachea into its major bronchi. It can be divided into anterior and posterior pulmonary plexuses, which are located in front and behind the tracheal bifurcation, respectively. These provide autonomic innervation to the lungs and the visceral pleura.

Both anterior and posterior pulmonary plexuses comprise of efferent autonomic neurons–sympathetic and parasympathetic–and visceral afferent neurons:

The post-ganglionic sympathetic neurons arise from the upper thoracic sympathetic ganglia. Whereas, the preganglionic parasympathetic neurons originate from the dorsal motor nucleus of vagus and arrive into the pulmonary plexus via the pulmonic branches of the right and left vagus nerves as they pass by the root of the lung. Autonomic neurons from the plexus, are eventually distributed along branches of airways and vessels, to the lungs and visceral pleura. Functionally, the sympathetic neurons cause bronchoconstriction, vasoconstriction and reduction in alveolar secretion. On the contrary, the vagal innervation leads to bronchodilatation, vasodilation and are secretomotor to bronchial and alveolar glands.

Please note that visceral afferent neurons also accompany the vagal and sympathetic efferent motor neurons. They transmit sensory information from the lungs and visceral pleura, back to the central nervous system.