Cardia

Infobox Anatomy
Name = Cardia
Latin =
GraySubject = 247
GrayPage = 1162


Caption = Diagram from [http://training.seer.cancer.gov/ss_module07_ugi/unit02_sec02_anatomy.html cancer.gov] :
* 1. Body of stomach
* 2. Fundus
* 3. Anterior wall
* 4. Greater curvature
* 5. Lesser curvature
* 6. Cardia
* 9. Pyloric sphincter
* 10. Pyloric antrum
* 11. Pyloric canal
* 12. Angular notch
* 13. Gastric canal
* 14. Rugal folds


Caption2 = Diagram of the stomach, showing its anatomical landmarks ("Antrum cardiacum" marks the opening of the cardia).
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Artery =
Vein =
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Lymph =
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DorlandsPre = c_10
DorlandsSuf = 12214493
The cardia (also known as Z-line or esophagogastric junction [eMedicineDictionary|esophagogastric+junction] or gastroesophageal junction [LoyolaMedEd|Radio/curriculum/GI/Image105b.jpg] [ [http://cellbio.utmb.edu/microanatomy/digestive/Esophagus.htm Lab Exercises- Esophagus ] ] [ [http://www.cancer.org/docroot/cri/content/cri_2_4_1x_what_is_esophagus_cancer_12.asp?sitearea=cri ACS :: What Is Cancer of the Esophagus? ] ] [ [http://www.cancer.gov/Templates/db_alpha.aspx?CdrID=302458 Definition of gastroesophageal junction - NCI Dictionary of Cancer Terms ] ] ) is the anatomical term for the junction orifice of the stomach and the esophagus. At the cardia, the mucosa of the esophagus transitions into gastric mucosa.

The cardia is also the site of the lower esophageal sphincter (LES) [ [http://hopkins-gi.nts.jhu.edu/pages/latin/templates/index.cfm?pg=disease1&organ=1&disease=13&lang_id=1 Digestive Disease Library ] ] [ [http://www.physio.unr.edu/ICC/gallery/LES-1.htm Department of Physiology and Cell Biology ] ] [eMedicine|med|2965] (also termed cardiac sphincter [eMedicineDictionary|cardiac+sphincter] , gastroesophageal sphincter, and esophageal sphincter [ [http://www.mcg.edu/Otolaryngology/patientGERD.htm Patient Handout: Gastroesophageal Reflux Disease (GERD) ] ] ).

Nomenclature and classification

There is disagreement in the academic anatomy community over whether the cardia is part of the stomach, part of the esophagus or a distinct entity, as described in this article. The difference is more than semantic when used in clinical studies and applied to individual patients.

Classical anatomy textbooks, and some other resources [SUNYAnatomyLabs|37|06|01|03 - "Abdominal Cavity: The Stomach"] , describe the cardia as the first of 4 regions of the stomach. This makes sense histologically because the mucosa of the cardia is the same as that of the stomach.

Many recent writings describe it as the esophageal sphincter.

Function

The stomach generates strong acids and enzymes to aid in food digestion. This digestive mixture is called gastric juice. The inner lining of the stomach has several mechanisms to resist the effect of gastric juice on itself, but the mucosa of the esophagus does not. The esophagus is normally protected from these acids by a one-way valve mechanism at its junction with the stomach. This one-way valve is called the esophageal sphincter (ES), and prevents gastric juice from flowing back into the esophagus.

During peristalsis, the ES allows the food bolus to pass into the stomach. It prevents chyme, a mixture of bolus, stomach acid, and digestive enzymes, from returning up the esophagus. The ES is aided in the task of keeping the flow of materials in one direction by the diaphragm.

Histology

On histological examination, the junction can be identified by the following transition: [BUHistology|11101loa] [BUHistology|11111ooa]

* nonkeratinized stratified squamous epithelium in the esophagus
* simple columnar epithelium in the stomach

However, in Barrett's esophagus, the epithelial distinction may vary, so the histological border may not be identical with the functional border.

The cardiac glands can be seen in this region. They can be distinguished from other stomach glands (fundic glands and pyloric glands) because the glands are shallow and simple tubular.

Pathology

Deficiencies in the strength or the efficiency of the LES lead to various medical problems involving acid damage on the esophagus.

In achalasia, one of the defects is failure of the LES to relax properly.

Removal

Surgical removal of this area is a called a cardiectomy a term that is also used to describe removal of the Heart. [ [http://dictionary.reference.com/browse/cardiectomy cardiectomy] at dictionary.reference.com] cite web | last =O. W. BARLOW | title =THE SURVIVAL OF THE CIRCULATION IN THE FROG WEB AFTER CARDIECTOMY | work = | publisher =Journal of Pharmacology And Experimental Therapeutics, Vol. 35, Issue 1, 17-24, 1929 | date = | url =http://jpet.aspetjournals.org/cgi/content/abstract/35/1/17 | format =web | accessdate = Feburuary 24, 2008 ] cite book | last =S.J. MELTZER | title =THE EFFECT OF STRYCHNIN IN CARDIECTOMIZED FROGS WITH DESTROYED LYMPH HEARTS | publisher =American Journal of Physiology | date =1913 | location = | pages =Page xix | url =http://books.google.com/books?id=pnsZI2vxfH8C&pg=RA1-PR19&dq=Cardiectomy&as_brr=1 | doi = | id = ]

Etymology

The word comes from the Greek "kardia" meaning "heart", the cardiac orifice of the stomach.

See also

* Artificial cardia, that can be used to fight, between other diseases, esophageal cancer, achalasia and gastroesophageal reflux disease.

=Additional

References