Esophagus

Esophagus
Head and neck.
Digestive organs. (oEsophagus is #1)
Details
Precursor	Foregut
Artery	oesophageal arteries
Vein	oesophageal veins
Nerve	celiac ganglia, vagus
Identifiers
Latin	Oesophagus(NECK)
MeSH	D004947
TA98	A05.4.01.001
TA2	2887
FMA	7131
Anatomical terminology

The esophagus or oesophagus (see American and British English 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. In humans the oesophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. It is usually 25-30 cm long which connects the mouth to the stomach. It is divided into cervical, thoracic, and abdominal parts. The trachea branches off the esophagus to the lungs.

Functions of the esophagus

Food is passed through the oesophagus by using the process of peristalsis. Specifically, it connects the pharynx, which is the body cavity that is common to the digestive factory and respiratory system with the stomach, where the second stage of digestion is initiated.

The oesophagus 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 swallowing sound that we hear is the esophagus functioning.

Histology

The layers of the esophagus are as follows:

• mucosa
  • nonkeratinized stratified squamous epithelium: is rapidly turned over, and serves a protective effect due to the high volume transit of food, saliva and mucous.
  • lamina propria: sparse.
  • muscularis mucosae: smooth muscle
• submucosa: Contains the mucous secreting glands (esophageal glands), and connective structures termed papillae.
• muscularis externa (or "muscularis propria"): composition varies in different parts of the oesophagus, to correspond with the conscious control over swallowing in the upper portions and the autonomic control in the lower portions:
  • upper third, or superior part: striated muscle
  • middle third, smooth muscle and striated muscle,
  • inferior third: predominantly smooth muscle.
• adventitia

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, but is actually more of a stricture.

Esophageal diseases and conditions

Many people experience a burning sensation in their chest occasionally, caused by stomach acids refluxing into the oesophagus, normally called heartburn. Extended exposure to heartburn may erode the lining of the oesophagus, leading potentially to Barrett's oesophagus which is associated an increased risk of adenocarcinoma most commonly found in the distal one-third of the oesophagus.

Some people also experience a sensation known as globus oesophagus, where it feels as if a ball is lodged in the lower part of the oesophagus.

The following are additional diseases and conditions that affect the oesophagus:

• Achalasia
• Chagas disease
• Caustic injury to the oesophagus
• Esophageal atresia and Tracheoesophageal fistula
• Esophageal cancer
• Esophageal web
• Esophagitis
• GERD
• Hiatus hernia
• Mallory-Weiss syndrome
• Neurogenic dysphagia
• Schatzki's ring
• Zenker's Diverticulum
• Boerhaave syndrome

Additional images

• H&E stain of biopsy of normal oesophagus showing the stratified squamous cell epithelium
  H&E stain of biopsy of normal oesophagus showing the stratified squamous cell epithelium
• 
  Layers of the esophagus.
• 
  Mid-esophageal mass
• 
  Stomach
• 
  Accessory digestive system.
• 
  Organs of the digestive tract.
• 
  Section of the neck at about the level of the sixth cervical vertebra.
• 
  Transverse section of thorax, showing relations of pulmonary artery.
• 
  Sagittal section of nose mouth, pharynx, and larynx.
• 
• 
  Section of the human oesophagus. Moderately magnified.
• 
  Microscopic shot of a cross section of human gastro-esophageal junction wall.

External links

• Template:IowaHistologyInteractive