Anterior Pulmonary Plexus
The Anterior and Posterior Pulmonary Plexuses supply the lung with afferent and efferent vagal and sympathetic fibers. The vagal fibers flatten out over the anterior and posterior aspects of the lung roots and intermingle with sympathetic fibers to form the anterior and posterior pulmonary plexuses. The vagal efferents are motor to the smooth muscle of the bronchi and pulmonary arterioles, shutting both down for economy of effort. Sympathetic efferents dilate pulmonary arterioles and bronchi to accommodate the increased cardiac output and increased pulmonary ventilation. The vagal and sympathetic afferents respond to bronchial stimulation, including pain.