Editing Esophagus (section)

===Microanatomy===
{{Main|Gastrointestinal wall}}
{{multiple image
| align       = right
| image1      = Tinción hematoxilina-eosina.jpg
| width1      = 250
| alt1        = Histological section of the esophageal wall.
| caption1    = [[H&E]] stain of a [[biopsy]] of the normal esophageal wall, showing the wall's [[stratified squamous epithelium]] 
| image2      = Gastro-esophageal jxn.JPG
| width2      = 120
| alt2        = Histological section showing the gastroesophageal junction, with a black arrow pointing to the junction.
| caption2    = [[Histology|Histological]] section of the gastroesophageal junction, with a black arrow indicating the junction
| image3      = Histology of Esophagus.svg
| width3      = 130
| alt3        = Schematic diagram showing all the four layers of the wall of the Esophagus
| caption3    = [[Schematic]] diagram showing all the four layers of the wall of the Esophagus
| link3       = https://commons.wikimedia.org/wiki/File:Histology of Esophagus.svg
| perrow      = 1/2
| total_width = 400
}}
{{Gastrointestinal wall series}}
The human esophagus has a [[mucous membrane]] consisting of a tough [[stratified squamous epithelium]] without [[keratin]], a smooth [[lamina propria]], and a [[muscularis mucosae]].<ref name=KUO2006 /> The epithelium of the esophagus has a relatively rapid turnover and serves a protective function against the abrasive effects of food. In many animals, the epithelium contains a layer of keratin, representing a coarser diet.<ref name="ross">{{cite book|title=Histology: A Text and Atlas|url=https://archive.org/details/histologytextatl00ross|url-access=limited|publisher=Lippincott Williams & Wilkins|vauthors=Ross M, Pawlina W|year=2011|isbn=978-0-7817-7200-6|pages=[https://archive.org/details/histologytextatl00ross/page/n590 571]–73|edition=6th}}</ref> 

The [[muscular layer]] of the esophagus has two types of muscle. The upper third of the esophagus contains [[striated muscle]], the lower third contains [[smooth muscle]], and the middle third contains a mixture of both.<ref name=KUO2006 /> Muscle is arranged in two layers: one in which the muscle fibers run longitudinal to the esophagus, and the other in which the fibers encircle the esophagus. These are separated by the [[myenteric plexus]], a tangled network of nerve fibers involved in the secretion of mucus and in peristalsis of the smooth muscle of the esophagus. The outermost layer of the esophagus is the [[adventitia]] in most of its length, with the abdominal part being covered in [[serosa]]. This makes it distinct from many other structures in the gastrointestinal tract that only have a serosa.<ref name=KUO2006 />

====Glands====
There are two types of glands, with mucus-secreting [[esophageal gland]]s being found in the [[submucosa]] and esophageal cardiac glands, similar to [[cardiac glands]] of the stomach, located in the lamina propria and most frequent in the terminal part of the organ.<ref name="ross"/><ref>{{cite book|last=Takubo|first=Kaiyo|title=Pathology of the esophagus an .|date=2007|publisher=Springer Verlag|location=Tokyo|isbn=978-4-431-68616-3|page=28|edition=2nd}}</ref> The [[mucus]] from the glands gives a good protection to the lining.<ref>{{cite book|editor-first=Barbara|editor-last=Young|title=Wheater's functional histology: a text and colour atlas|url=https://archive.org/details/wheatersfunction00youn|url-access=limited|date=2006|publisher=Churchill Livingstone/Elsevier|isbn=978-0-443-06850-8|page=[https://archive.org/details/wheatersfunction00youn/page/n169 86]|edition=5th}}</ref> The submucosa also contains the [[submucosal plexus]], a network of [[neuron|nerve cells]] that is part of the [[enteric nervous system]].<ref name=ross />