Esophagus

Illustration of the digestive tract showing: mouth, esophagus, stomach, large intestine (colon) small intestine, ileum, rectum, and anus. Source: Wikimedia Commons

Other Names

• Gullet is synonymous with esophagus.
• Oesophagus is an alternate spelling.

Description

The esophagus is a muscular tube that connects the pharynx to the stomach. In adults it is about 23 cm long. It begins in the neck at about the level of the sixth cervical vertebra, travels close to the trachea and heart as it traverses the chest, and enters the abdomen when it passes through the diaphragm, after which it connects with the stomach at the level of the eleventh thoracic vertebra. The esophagus is the narrowest part of the digestive tube, and food spends only a few seconds traveling through it. Special muscles called sphincters keep the esophagus closed at the upper end (the upper esophageal sphincter, UES) and at the lower end (the lower esophageal sphincter, LES). There are four distinct layers to the wall of the esophagus—the outermost fibrous layer, which surrounds a muscular layer, a submucosal layer containing blood vessels and nerves, and an innermost mucosal layer that is exposed to passing food.

Role of the Esophagus in the Body

The esophagus is an organ of the digestive system. Its role is to convey swallowed material to the stomach. Much less frequently, the esophagus allows rapid elimination of stomach contents in a process known as vomiting or emesis. Unlike the rest of the gut, the esophagus plays a very minor role in digestion, nutrient absorption, and food storage.

How It Works

Under normal circumstances, foods, liquids, and saliva enter the esophagus by a coordinated and voluntary set of muscular contractions known as swallowing or deglutition. Involuntary muscular contractions and relaxations take over once food enters the esophagus that allow one-way passage of material down the esophagus. To accomplish this, muscles relax in front of where the food is located. Food is pushed from behind by muscular contraction. This wave-like motion of muscular contraction and relaxation is known as peristalsis. Gravity plays a minor role in moving food through the esophagus. The peristaltic contractions allow successful eating and drinking while lying down, or even while being turned upside down.

Sometimes the esophagus conveys stomach contents to the mouth (and sometimes the nose) in a process known as vomiting. Regurgitation refers to the return of undigested food that has not yet reached the stomach.

Diseases of the Esophagus

Injuries to the esophagus can occur after swallowing liquids that are stongly acidic or basic, extremely hot, or extremely cold. Solid items that are swallowed can also injure the esophagus if they have sharp edges or points. Occasionally, swallowed items become stuck at the narrowest point of the esophagus, where it crosses the diaphragm.

Vomited material can also injure the esophagus. Stomach contents are normally acidic, and directly irritate the esophageal lining. Swallowed material that proves irritating to the stomach once it arrives can re-injure the esophagus as it leaves.

Since the esophagus has a relatively small surface area and since food spends such a short amount of time traveling through it, the esophagus accounts for a relatively small proportion of gastrointestinal diseases. Perhaps the most common disease of the esophagus is gastroesophageal reflux disease, or GERD, also known as heartburn. This is usually caused by a leaky lower esophageal sphincter that allows stomach contents to enter the esophagus. Large meals and spicy foods sometimes lead to especially unpleasant bouts of GERD. Several popular medicines exist to lower the acidity of the stomach contents and reduce the symptoms of GERD; examples include ranitidine (Zantac) and famotidine (Pepcid) . In some cases, surgical intervention may be appropriate, alone or in combination with medical therapy.^[1]

Barrett's esophagus may be related to GERD. To make the diagnosis, a doctor usually uses an endscope, with which the doctor can see and biopsy abnormal cells at the lowefr end of the esophagus. These changes can be seen under the microscope. Barrett's esophagus may precede the development of adenocarcinoma of the esophagus. The risk of developing adenocarcinoma is 30 to 125 times higher in people who have Barrett's esophagus than in people who do not.^[2] Several options for prevention and treatment are available.^[3]

The appearance of scar tissue during recovery from injury can impair normal functioning of the esophagus. Specifically, the esophagus must expand to allow passage of food, and the inability to expand normally can cause significant discomfort or pain with swallowing (dysphagia). These abnormal constrictions (strictures) can often be resolved by insertion of a catheter surrounded by an uninflated balloon into the esophagus, and inflation of the balloon to forcibly expand the lumen of the esophagus at the point of stricture. The balloon size must be carefully selected to balance the need for easy food passage with the need to avoid injuring the organ further; a 45 French (15 mm diameter) catheter seems to give good results.^[4]

Related Professions

Gastroenterology is the medical specialty that deals with diseases of the gut.

References

1. ↑ Heidelbaugh JJ, Nostrant TT, Kim C, Van Harrison R. Management of gastroesophageal reflux disease. Am Fam Physician. 2003 Oct 1;68(7):1311-8. Abstract | Full Text | PDF
2. ↑ Reid BJ. Barrett's esophagus and esophageal adenocarcinoma. Gastroenterol Clin North Am. 1991 Dec;20(4):817-34. Abstract
3. ↑ Modiano N, Gerson LB. Barrett's esophagus: Incidence, etiology, pathophysiology, prevention and treatment. Ther Clin Risk Manag. 2007 Dec;3(6):1035-145. Abstract | Full Text | PDF
4. ↑ Raymondi R, Pereira-Lima JC, Valves A, et al. Endoscopic dilation of benign esophageal strictures without fluoroscopy: experience of 2750 procedures. Hepatogastroenterology. 2008 Jul-Aug;55(85):1342-8. Abstract