NEET PG DENTAL EXAM

Detailed explanation-1: -The parasympathetic nervous system (PNS) stimulates peristalsis via the myenteric plexus. The afferent (sensory) nerves of the myenteric plexus deliver information to interneurons within the plexus. Interneurons communicate with efferent nerves, stimulating an action potential (spike-wave) within smooth muscle cells.

Detailed explanation-2: -Esophageal peristalsis is controlled by central and peripheral neural mechanisms involving extrinsic sympathetic or parasympathetic nerves and myenteric plexus respectively. Furthermore, innervation differs between the striated and the smooth muscle.

Detailed explanation-3: -Esophageal peristalsis results from sequential contraction of circular muscle, which serves to push the ingested food bolus toward the stomach. Esophageal longitudinal muscle may also play a role in peristalsis.

Detailed explanation-4: -The esophagus is innervated by both parasympathetic and sympathetic nerves. The parasympathetics control peristalsis via the vagus nerve. The medullary vagal postganglionic efferents arise from the lower motor neurons in the nucleus retrofacialis and the compact formation of the nucleus ambiguus.