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The esophageal plexus (oesophageal plexus in British English) is formed by nerve fibers from two sources, branches of the vagus nerve, [1] [2] and visceral branches of the sympathetic trunk. [3] [4] The esophageal plexus and the cardiac plexus contain the same types of fibers and are both considered thoracic autonomic plexus.
Between the two muscle layers is the myenteric plexus (Auerbach's plexus). This controls peristalsis. Activity is initiated by the pacemaker cells (interstitial cells of Cajal). The gut has intrinsic peristaltic activity (basal electrical rhythm) due to its self-contained enteric nervous system.
The anterior vagal trunk is one of the two divisions (the other being the posterior vagal trunk) into which the vagus nerve splits as it passes through the esophageal hiatus to enter the abdominal cavity. [1] The anterior and posterior vagal trunks represent the inferior continuation of the esophageal nervous plexus inferior to the diaphragm. [2]
The muscularis mucosae is composed of several thin layers of smooth muscle fibers oriented in different ways which keep the mucosal surface and underlying glands in a constant state of gentle agitation to expel contents of glandular crypts and enhance contact between epithelium and the contents of the lumen.
The esophagus is innervated by the vagus nerve and the cervical and thoracic sympathetic trunk. [6] The vagus nerve has a parasympathetic function, supplying the muscles of the esophagus and stimulating glandular contraction. Two sets of nerve fibers travel in the vagus nerve to supply the muscles.
The fibers are carried by both the anterior and posterior vagal nerves. The myenteric plexus is the major nerve supply to the gastrointestinal tract and controls GI tract motility. [1] According to preclinical studies, 30% of myenteric plexus' neurons are enteric sensory neurons, thus Auerbach's plexus has also a sensory component. [2] [3]
The inferior fibers are horizontal and continuous with the circular fibers of the esophagus; the rest ascend, increasing in obliquity, and overlap the middle pharyngeal constrictor muscle. The cricopharyngeal part is synonymous with the upper esophageal sphincter (UES), which controls the opening of the cervical esophagus. [4]
The submucosa (or tela submucosa) is a thin layer of tissue in various organs of the gastrointestinal, respiratory, and genitourinary tracts. It is the layer of dense irregular connective tissue that supports the mucosa (mucous membrane) and joins it to the muscular layer, the bulk of overlying smooth muscle (fibers running circularly within layer of longitudinal muscle).