The lungs are supplied by both the sympathetic and parasympathetic divisions of the autonomic nervous system, arranged as the PULMONARY PLEXI. These paired autonomic plexi lie on the anterior and posterior surfaces of the roots of both lungs. The pulmonary plexi are directly continuous with the cardiac plexus at the tracheal bifurcation, and communicate with the esophageal plexus and autonomic fibers on the aorta. Fibers from the pulmonary plexi distribute to smooth muscle and glands of the bronchi and pulmonary blood vessels.