Esophagus
The
esophagus (also spelled
oesophagus/
"sophagus), or
gullet is the muscular tube in
vertebrates through which ingested food passes from the mouth area to the
stomach. The esophagus is continuous with the laryngeal part of the
pharynx at the level of the C6 vertebra.
The esophagus is
histologically broken down into 3 parts.
* The superior portion consists primarily of
striated muscle.
* The middle portion consists of mixed striated and
smooth muscle.
* The inferior 1/3 consists primarily of smooth muscle.
Food is passed through the esophagus by using the process of
peristalsis. Specifically, in
mammals, it connects the
pharynx, which is the body cavity that is common to the
digestive system and
respiratory system behind the
mouth (
buccal cavity), with the
stomach, where the second stage of digestion is initiated (the first stage of digestion is in the mouth, with
teeth and
tongue masticating
food and mixing it with
saliva).
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.
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 valve,
cardia or cardias, but is actually more of a stricture. Many people experience
acid reflux, where stomach acid gets pushed up into the esophagus, causing a burning sensation, commonly termed
heartburn. Extended exposure to heartburn may erode the lining of the esophagus, leading to a potentially cancerous condition called
Barrett's Esophagus.
Some people also experience a sensation known as
globus esophagus, where it feels as if a ball is lodged in the lower part of the esophagus.
The word "esophagus" is the result of the "o" being dropped from the oe (or
") in "oesophagus". It derives from Greek; οiσω -oeso, future tense of the verb φερω-to bring and from the verb έφαγον,-phagus, past tense of τρώγω-to eat.
The following are diseases and conditions that affect the esophagus:
*
Achalasia*
Chagas disease*
Caustic injury to the esophagus
*
Esophageal atresia and
Tracheoesophageal fistula*
Esophageal cancer*
Esophageal spasm*
Esophageal speech*
Esophageal stricture*
Esophageal varices*
Esophageal web*
Esophagitis*
GERD*
Hiatus hernia*
Mallory-Weiss syndrome*
Neurogenic dysphasia*
Plummer-Vinson syndrome*
Schatzki's ring*
Zenker's diverticulum
