Cardia

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Cardia
Image:Illu stomach.jpg
Diagram from 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
Image:Gray1046.svg
Diagram of the stomach, showing its anatomical landmarks ("Antrum cardiacum" marks the opening of the cardia).
Dorlands/Elsevier	c_10/12214493

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This article is about the cardia in the human body. For the city in Greece, see Cardia (Thrace).

The cardia 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) (also termed cardiac sphincter and gastroesophageal sphincter).

1 Nomenclature and classification
2 Function
3 Pathology
4 Etymology
5 See also
6 Additional images
7 External links

[edit] 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 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.

Recent writings describe it as the LES.

[edit] 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 lower esophageal sphincter (LES), and prevents gastric juice from flowing back into the esophagus.

During peristalsis, the LES 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 LES is aided in the task of keeping the flow of materials in one direction by the diaphragm.