The LES is sometimes called the gastroesophageal sphincter or gastroesophageal junction because of the two structures it connects.
(Gastro means stomach.)
Its sometimes referred to as the cardiac sphincter as well because of its proximity to theheart.
Verywell / Michela Buttignol
How Does the Lower Esophageal Sphincter Work?
The LES is classified as a functional (or physiological) sphincter.
Functional sphincters don’t have a thickened ring of muscles like anatomical sphincters do.
Instead, they have a circular muscle that works by constricting either around or inside of them.
This specialized structure cant be visually identified as a sphincter unless its constricted.
When its relaxed, it looks just like the surrounding tissues.
The LES is also considered an involuntary sphincter.
Nerve stimulation for involuntary sphincters comes from autonomic nerves, which are part of theautonomic nervous system.
It deals with automatic processes, including the function of glands and internal organs.
Asphincteris a ring of muscle that guards or closes the end of a tube.
You have several of them in your digestive system and elsewhere throughout your body.
They control the passage of liquids, solids, and gases.
The opening of a sphincter is called thelumen.
When the sphincter contracts, the muscle shortens and the lumen closes.
When the sphincter muscle relaxes, it lengthens and causes the lumen to open.
Location
The esophagus starts at the bottom of thepharynx(throat).
From there, it descends behind thetrachea(windpipe) and the heart.
It then passes through thediaphragm, which is a membrane that sits just below the lungs.
What Are the Other Digestive System Sphincters?
What Does the Lower Esophageal Sphincter Do?
The lower esophageal sphincter remains closed except for when you swallow.
Then, it opens to allow food to move down into the stomach.
Food enters the throat, and then both esophageal sphincters open.
The LES stays open for about five seconds after you swallow.
It then closes to keep food and digestive enzymes from washing back up into the esophagus.
This is called acid reflux.
The main symptom of acid reflux isheartburn.
If you have frequent heartburn, its important to treat it.
There are four types of hiatal hernia.
This is also called a sliding hiatal hernia.
It can predispose you to GERD.
bang out II involves herniation of the stomach.
jot down III involves the stomach and LES.
pop in IV involves another organ, such as thecolonorspleen.
However, if you develop GERD, your hernia does need to be treated.
In cases where the blood supply is cut off to the herniation, surgery is necessary.
It involves pulling the herniated portion out of the diaphragm’s hole and closing it.
The surgeon also strengthens the LES by wrapping the upper part of the stomach around it.
This procedure creates a permanently tight sphincter to prevent reflux.
Achalasia
Achalasia is an inability to swallow or pass food from the esophagus to the stomach.
The cause is usually unknown.
Muscle relaxants such as Nitrostat (nitroglycerin) or Procardia (nifedipine) may help as well.
Theyre typically used only when other treatments fail or arent an option.
Hypertensive Lower Esophageal Sphincter
Hypertensive LES involves increased muscle contraction.
The cause is often unknown, but it is sometimes related to GERD.
Symptoms of hypertensive LES often get worse slowly over time.
They include:
Treatment is often myotomya minimally invasive surgery similar to that used for achalasia.
It’s inserted through the nose or mouth.
Its a common test when a doctor suspects a structural or inflammatory problem.
Esophageal pH Monitoring
This test is considered the gold standard for diagnosing GERD.
It involves 24-hour monitoring of the acid levels in the lower esophagus, near the LES.
It involves placing a thin catheter that detects acid in the esophagus.
The test reveals how many episodes of high acid you have and how long acid levels are elevated.
Esophageal Manometry
Esophageal manometryinvolves a small tube with pressure sensors.
Its placed in the stomach via the nose or mouth and then slowly withdrawn.
The tube measures pressure at different points along the way.
That includes the luminal (opening) pressure in both esophageal sphincters and throughout the esophagus.
Its job is to stop stomach contents from leaking into the esophagus and mouth.
Johns Hopkins Medicine.Gastroesophageal reflux disease (GERD).
University of California Los Angeles Health.Scleroderma.
Merck Manual.Medicines for the treatment of gastric acidity.
Johns Hopkins Medicine.Gastroesophageal reflux disease (GERD) treatment.
Johns Hopkins Medicine.Hiatal hernia.
International Foundation for Functional Gastrointestinal Disorders.Disorders of the esophagus.
International Foundation for Functional Gastrointestinal Disorders.Achalasia.
University of California San Francisco Department of Surgery.Heller myotomy.
Memorial Hermann Foundation.Hypertensive lower esophageal sphincter.
Johns Hopkins Medicine.Barium swallow.
American Society for Gastrointestinal Endoscopy.Esophageal manometry & 24-hour pH and impedance tests.
Vogt CD, Panoskaltsis-Mortari A.Tissue engineering of the gastroesophageal junction.J Tissue Eng Regen Med.
2020;14(6):855-868. doi:10.1002/term.3045
