Copyright 2008
Introduction
The esophagus is basically a tube that has the ability to contract and relax
The esophagus is basically a tube as seen in the first image on left, which has the ability to initiate strong contractions (middle image) as well as actively relax. (right image).
Ashley Davidoff, M.D. TheCommonVein.net
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.
The esophagus lies between two sphincters. The upper esophageal sphincter (UES) enables food to enter the esophagus while the lower esophageal sphincter (LES) prevents reflux of gastric contents.
Ashley Davidoff, M.D. TheCommonVein.net
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 basal state with both sphincters contracted. As the food enters the oropharynx from the mouth, the UES relaxes, and the receiving segment of the esophagus just distal to the UES reflexly relaxes as well. (b) In c, the UES contracts behind the bolus and a primary stripping wave are formed that rapidly advances the bolus. Simultaneously the LES relaxes (d). The bolus gets pushed through the LES which subsequently contracts behind the bolus and we are back to the basal state (f).
Ashley Davidoff, M.D. TheCommonVein.net
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.