Principles Structure

The Common Vein  Copyright 2008

Introduction

The esophagus is basically a tube that has the ability to contract and relax

The Esophagus

A Tube that has the Ability to Contract and Relax

The esophagus is basically a tube (a), that has the ability to initiate strong contractions (b) as well as actively relax. (c)

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As the most muscular organ in the gastrointestinal tract its function is to rapidly transfer the bolus of food or fluid from the upper esophageal sphincter to the lower esophageal sphincter and then to the stomach.  This requires exquisite coordination of muscle contraction and relaxation.  As the bolus reaches the back of the oropharynx, reflex relaxation of the UES has to occur, briefly to allow the food to enter, and then it has to close rapidly to prevent reflux.

Upper and Lower Esophageal Sphincter – “At Rest”

At rest the upper and lower esophageal sphincters are contracted in order to prevent reflux of gastric contents into the esophagus and airways.

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A Tube with Coordinated Effort of Contraction and Relaxation

The six drawings above reflect the contractile and relaxation efforts of the esophagus in order to transport a food and or fluid bolus from the back of the mouth to the stomach.  The resting phase in a shows the UES and LES in contraction.  As the food enters the oropharynx from the mouth, the UES relaxes, as the receiving segment reflexly relaxes. (b)  In c, the UES contracts behind the bolus and a primary stripping wave is formed that rapidly advances the bolus.  Simultaneously the LES relaxes (d).  The bolus get pushed through the LES which subsequently contracts behind the bolus.(f)

73368c03.800 esophagus normal motility contraction wave peristalsis primary stripping wave physiology function receptive relaxation upper esophageal sphincter lower esophageal sphincter LES UES esophageal body pharynx Davidoff Art Courtesy Ashley Davidoff MD

As long as the lumen is greater than 13mms in diameter food will not get stuck.  As the lumen narrows in disease to 13mms. or less dysphagia will occur.