Gullet" redirects here. For other uses, see Gullet (disambiguation).
Esophagus
Tractus intestinalis esophagus.svg
The digestive tract, with the esophagus marked in red
Details
Precursor	Foregut
System	Digestive system
Artery	Esophageal arteries
Vein	Esophageal veins
Nerve	Sympathetic trunk, vagus
Identifiers
Latin	Oesophagus
MeSH	D004947
TA98	A05.4.01.001
TA2	2887
FMA	7131
Anatomical terminology
[edit on Wikidata]
Stomach colon rectum diagram-en.svg
Major parts of the
Gastrointestinal tract
Upper gastrointestinal tract
Lower gastrointestinal tract
See also
vte
The esophagus (American English) or oesophagus (British English, see spelling differences; both /iːˈsɒfəɡəs, ɪ-/[1]), colloquially known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 cm (10 in) long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, “I carry”) + ἔφαγον (éphagon, “I ate”).

The wall of the esophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epithelium of around three layers of squamous cells, which contrasts to the single layer of columnar cells of the stomach. The transition between these two types of epithelium is visible as a zig-zag line. Most of the muscle is smooth muscle although striated muscle predominates in its upper third. It has two muscular rings or sphincters in its wall, one at the top and one at the bottom. The lower sphincter helps to prevent reflux of acidic stomach content. The esophagus has a rich blood supply and venous drainage. Its smooth muscle is innervated by involuntary nerves (sympathetic nerves via the sympathetic trunk and parasympathetic nerves via the vagus nerve) and in addition voluntary nerves (lower motor neurons) which are carried in the vagus nerve to innervate its striated muscle.

The esophagus passes through the thoracic cavity into the diaphragm into the stomach.

The esophagus may be affected by gastric reflux, cancer, prominent dilated blood vessels called varices that can bleed heavily, tears, constrictions, and disorders of motility. Diseases may cause difficulty swallowing (dysphagia), painful swallowing (odynophagia), chest pain, or cause no symptoms at all. Clinical investigations include X-rays when swallowing barium sulfate, endoscopy, and CT scans. Surgically, the esophagus is difficult to access in part due to its position between critical organs and directly between the sternum and spinal column.[2]

Structure
The esophagus is one of the upper parts of the digestive system. There are taste buds on its upper part.[3] It begins at the back of the mouth, passing downward through the rear part of the mediastinum, through the diaphragm, and into the stomach. In humans, the esophagus generally starts around the level of the sixth cervical vertebra behind the cricoid cartilage of the trachea, enters the diaphragm at about the level of the tenth thoracic vertebra, and ends at the cardia of the stomach, at the level of the eleventh thoracic vertebra.[4] The esophagus is usually about 25 cm (10 in) in length.[5]

Many blood vessels serve the esophagus, with blood supply varying along its course. The upper parts of the esophagus and the upper esophageal sphincter receive blood from the inferior thyroid artery, the parts of the esophagus in the thorax from the bronchial arteries and branches directly from the thoracic aorta, and the lower parts of the esophagus and the lower esophageal sphincter receive blood from the left gastric artery and the left inferior phrenic artery.[6][7] The venous drainage also differs along the course of the esophagus. The upper and middle parts of the esophagus drain into the azygos and hemiazygos veins, and blood from the lower part drains into the left gastric vein. All these veins drain into the superior vena cava, with the exception of the left gastric vein, which is a branch of the portal vein.[6] Lymphatically, the upper third of the esophagus drains into the deep cervical lymph nodes, the middle into the superior and posterior mediastinal lymph nodes, and the lower esophagus into the gastric and celiac lymph nodes. This is similar to the lymphatic drainage of the abdominal structures that arise from the foregut, which all drain into the celiac nodes.[6]nucleus ambiguus, whereas fibers that supply the smooth muscle and lower esophageal sphincter have bodies situated in the dorsal motor nucleus.[6] The vagus nerve plays the primary role in initiating peristalsis.[12] The sympathetic trunk has a sympathetic function. It may enhance the function of the vagus nerve, increasing peristalsis and glandular activity, and causing sphincter contraction. In addition, sympathetic activation may relax the muscle wall and cause blood vessel constriction.[6] Sensation along the esophagus is supplied by both nerves, with gross sensation being passed in the vagus nerve and pain passed up the sympathetic trunk.[4]

Gastro-esophageal junction
The gastro-esophageal junction (also known as the esophagogastric junction) is the junction between the esophagus and the stomach, at the lower end of the esophagus.[13] The pink color of the esophageal mucosa contrasts to the deeper red of the gastric mucosa,[6][14] and the mucosal transition can be seen as an irregular zig-zag line, which is often called the z-line.[15] Histological examination reveals abrupt transition between the stratified squamous epithelium of the esophagus and the simple columnar epithelium of the stomach.[16] Normally, the cardia of the stomach is immediately distal to the z-line[17] and the z-line coincides with the upper limit of the gastric folds of the cardia; however, when the anatomy of the mucosa is distorted in Barrett's esophagus the true gastro-eshophageal junction can be identified by the upper limit of the gastric folds rather than the mucosal transition.[18] The functional location of the lower oesophageal sphincter is generally situated about 3 cm (1+1⁄4 in) below the z-line.[6]