Esophagus
Say it: ih-SOF-uh-gus
The esophagus is the muscular tube, about 25 centimeters long, that carries swallowed food and liquid from the pharynx down to the stomach.
UK spelling: oesophagus
Also: gullet, food pipe
Definition
What is the esophagus?
The esophagus begins in the neck as the continuation of the lowest part of the pharynx, at about the sixth cervical vertebra (C6). It runs down through the mediastinum, behind the trachea and the heart and in front of the vertebral column, passes through the esophageal hiatus of the diaphragm and opens into the stomach. Between swallows it lies flat and collapsed.
Its lining is a tough, non-keratinized stratified squamous epithelium with mucus glands that protect it from rough food. The muscle coat changes along its length, from skeletal muscle in the upper third, through a mixture, to smooth muscle in the lower third, and its outer layer is loose connective tissue, the adventitia, rather than the serosa found on most of the gut. Swallowing starts waves of peristalsis that push a food bolus to the stomach in a few seconds. An upper esophageal sphincter keeps air out, and a lower esophageal sphincter at the junction with the stomach relaxes to let food through and then tightens to stop acid flowing back.
When the lower sphincter is weak, acid reflux causes heartburn and gastroesophageal reflux disease. Years of reflux can replace the lining with intestine-like columnar cells, a change called Barrett's esophagus, which raises the risk of esophageal adenocarcinoma.
Word parts
Where does the word “esophagus” come from?
- eso-
- will carryGreek ois-, a stem of pherein (to carry)
- -phagus
- eating, foodGreek phagein (to eat)
Practice it
Where you'll meet it
Related
Terms that go with it
- PharynxThe pharynx, or throat, is the muscular tube behind the nose and mouth that carries air to the larynx and food to the esophagus.
- StomachThe stomach is a J-shaped, muscular sac of the digestive tract that stores food, churns it with acid and enzymes, and starts the digestion of protein.
- DigestionDigestion is the process by which the body breaks food down, by chewing, churning and enzymes, into molecules small enough to absorb into the blood.
- DiaphragmIn anatomy, the diaphragm is the dome-shaped sheet of muscle and tendon dividing the chest from the abdomen, and the main muscle of breathing.
- MetaplasiaMetaplasia is the replacement of one mature cell type by another in a tissue, usually as an adaptation to long-term irritation or injury.
- MediastinumThe mediastinum is the middle region of the chest, between the two lungs, that holds the heart, great vessels, trachea, esophagus and thymus.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Anatomy and Physiology 2e, 23.3 The Mouth, Pharynx, and Esophagus
- SEER Training Modules: Pharynx and Esophagus
- TeachMeAnatomy: The Oesophagus
Last updated
Spotted a mistake? Tell us and we'll correct it.
Practice Human Anatomy
Free human anatomy quizzes, with an explanation for every answer.
See the Quizzes