Esophagus

From Wikipedia, the free encyclopedia

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (December 2007)

Esophagus
Head and neck.
Digestive organs. (Esophagus is #1)
Latin	Oesophagus(NECK)
Gray's	subject #245 1144
Artery	esophageal arteries
Vein	esophageal veins
Nerve	celiac ganglia, vagus[1]
Precursor	Foregut
MeSH	oEsophagus
Dorlands/Elsevier	e_16/12343479

The esophagus or oesophagus (see American and British English spelling differences), sometimes known as the gullet, is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. In humans the esophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. It is usually 25-30 cm long which connects the mouth to the stomach. It is divided into cervical, thoracic, and abdominal parts.

Contents 1 Functions of the esophagus 2 Histology 3 Gastroesophageal junction 4 See also 5 Additional images 6 References 7 External links

[edit] Functions of the esophagus

Food is passed through the esophagus by using the process of peristalsis. Specifically, it connects the pharynx, which is the body cavity that is common to the digestive factory and respiratory system with the stomach, where the second stage of digestion is initiated.

The esophagus is lined with mucous membrane, and is more deeply lined with muscle that acts with peristaltic action to move swallowed food down to the stomach.

[edit] Histology

The layers of the esophagus are as follows:^[2]

• mucosa
  • nonkeratinized stratified squamous epithelium: is rapidly turned over, and serves a protective effect due to the high volume transit of food, saliva and mucus.
  • lamina propria: sparse.
  • muscularis mucosae: smooth muscle
• submucosa: Contains the mucous secreting glands (esophageal glands), and connective structures termed papillae.
• muscularis externa (or "muscularis propria"): composition varies in different parts of the esophagus, to correspond with the conscious control over swallowing in the upper portions and the autonomic control in the lower portions:
  • upper third, or superior part: striated muscle
  • middle third, smooth muscle and striated muscle,
  • inferior third: predominantly smooth muscle.
• adventitia

[edit] Gastroesophageal junction

The junction between the esophagus and the stomach (the gastroesophageal junction or GE junction) is not actually considered a valve, although it is sometimes called the cardiac sphincter, cardia or cardias, but is actually more of a stricture.

[edit] See also

• Esophageal disease

[edit] Additional images

H&E stain of biopsy of normal esophagus showing the stratified squamous cell epithelium	Layers of the esophagus.	Mid-esophageal mass	Stomach
Accessory digestive system.	Organs of the digestive tract.	Section of the neck at about the level of the sixth cervical vertebra.	Transverse section of thorax, showing relations of pulmonary artery.
Sagittal section of nose mouth, pharynx, and larynx.	The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind. |	Section of the human esophagus. Moderately magnified.	Microscopic shot of a cross section of human gastro-esophageal junction wall.

[edit] References

1. ^ Physiology at MCG 6/6ch2/s6ch2_30
2. ^ Histology at BU 10801loa

[edit] External links

• Virtual Slidebox at Univ. Iowa Slide 449

v • d • e Anatomy of torso, digestive system: Gastrointestinal tract Upper GI: to stomach Mouth • Pharynx (nasopharynx, oropharynx, hypopharynx) • Esophagus • Crop Upper GI: stomach rugae – gastric pits – cardia/gland – fundus/gland – pylorus/gland – pyloric antrum – pyloric canal – greater curvature – lesser curvature – angular incisure Lower GI: intestines Small intestine: Duodenum (Suspensory muscle, Major duodenal papilla, Minor duodenal papilla) • Duodenojejunal flexure • Jejunum • Ileum • continuous (intestinal villus, crypts of Lieberkühn, circular folds) Junction: Vermiform appendix • Ileocecal valve Large intestine: Cecum • Colon (ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon) • continuous (taenia coli, haustra, epiploic appendix) Lower GI: termination Rectum: Houston valve • rectal ampulla • pectinate line Anal canal: anal valves • anal sinuses • anal columns • Hilton's white line Anus: Sphincter ani internus muscle • Sphincter ani externus muscle Lower GI: lymph GALT: Peyer's patches (M cells)