Esophagus: Wikis

  

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Esophagus
Illu01 head neck.jpg
Head and neck.
BauchOrgane wn.png
Digestive organs. (Esophagus is #1)
Latin œsophagus
Gray's subject #245 1144
Artery esophageal arteries
Vein esophageal veins
Nerve celiac ganglia, vagus[1]
Precursor Foregut
MeSH oesophagus
Dorlands/Elsevier Esophagus

The esophagus or oesophagus (see 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. The word esophagus is derived from the Latin œsophagus, which derives from the Greek word oisophagos (οισοφάγος), lit. "entrance for eating." In humans the esophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. The esophagus passes through a hole in the diaphragm at the level of the tenth thoracic vertebrae (T10). It is usually about 25–30 cm long and connects the mouth to the stomach. It is divided into abdominal parts.

Contents

Histology

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

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, although it is actually better resembles a stricture.

In other animals

In most fish, the esophagus is extremely short, primarily due to the length of the pharynx (which is associated with the gills). However, some fish, including lampreys, chimaeras, and lungfish, have no true stomach, so that the oesophagus effectively runs from the pharynx directly to the intestine, and is therefore somewhat longer.[3]

In tetrapods, the pharynx is much shorter, and the esophagus correspondingly longer, than in fish. In amphibians, sharks and rays, the esophageal epithelium is ciliated, helping to wash food along, in addition to the action of muscular peristalsis. In the majority of vertebrates, the esophagus is simply a connecting tube, but in birds, it is extended towards the lower end to form a crop for storing food before it enters the true stomach.[3]

A structure with the same name is often found in invertebrates, including molluscs and arthropods, connecting the oral cavity with the stomach

See also

Additional images

References

  1. ^ Physiology at MCG 6/6ch2/s6ch2_30
  2. ^ Histology at BU 10801loa
  3. ^ a b Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 344-345. ISBN 0-03-910284-X. 

External links


Wikibooks

Up to date as of January 23, 2010
(Redirected to Human Digestive System/Esophagus article)

From Wikibooks, the open-content textbooks collection

< Human Digestive System

The esophagus is a soft tube that is usually about 25 centimeters in length. When food or liquids are passed from the mouth, it is pushed down the esophagus by circular muscles. These muscles squeeze in top to bottom order, pushing the food and liquid down, like toothpaste being pushed through a tube. At the bottom of the esophagus is a barrier called a sphincter. This muscle is like a door that opens to let the esophagus contents enter the stomach. The sphincter then closes to keep stomach contents from coming up. Sometimes this muscle doesn't work well and stomach juices splash into the esophagus causing acid reflux and heartburn.








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