A Definition of the Upper Esophageal Sphincter

Why this body part plays a key role in the development of acid reflux

male stomach illustration
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Definition: The upper esophageal sphincter is a muscular valve that is located at the upper portion of the esophagus, which is typically about 8 inches long.

Unlike the lower esophageal sphincter (LES), which opens and closes without our conscious effort, the upper esophageal sphincter is under our conscious control. We can control when it opens. For example, we can open the upper esophageal sphincter by swallowing foods or liquids.

The Upper Esophageal Sphincter at Work

During swallowing, the upper esophageal sphincter opens to allow food and liquids to pass into the esophagus. It can also reduce the back flow of food and liquids from the esophagus into the pharynx

In addition to eating, we use this part of the esophagus while simply breathing. It also comes into play during unpleasant bodily functions, such as burping or throwing up, that serve to expel gas or harmful materials from the body.

The cluster of muscles that make up the upper esophageal sphincter prevent food from traveling down the trachea, or windpipe. This is known as aspiration and refers to foreign materials in the airway. Aspiration can lead to choking or even pneumonia if food journeys to the lungs. When food goes down the "wrong pipe," the best advice is to cough, which helps the food go down the esophagus instead.

Also Known As: The upper esophageal sphincter is abbreviated as UES.

It is also known as the inferior pharyngeal sphincter since it's positioned at the lower end of pharynx and protects the opening into the esophagus

When the UES Malfunctions

If the upper esophageal sphincter doesn't function properly, acid that has flowed back into the esophagus is allowed into the throat.

This can lead to painful medical conditions, such as heartburn or gastroesophageal reflux disease (GERD), the term used to describe repeated cases of heartburn.

Why the UES Is Unique

The UES plays a special role in regulating the passage of food and liquid down the throat, but it and the LES are not the only sphincters in the body. There's also the anal sphincter, the muscle group near the anus that regulates the passage of stool out of the body. Then, there's the sphincter of Oddi, which regulates the passage of bile and pancreatic secretions into the small intestine.

While sphincters appear in different areas of the body, they all function to control the flow of substances through organs and to open and shut different body parts. Sphincters play an important role in keeping the body sound and healthy.

Wrapping Up

While learning about the body parts that play key roles in the development of acid reflux won't make your discomfort disappear, it can turn you into an informed patient, knowledgeable enough to pursue a variety of options to find the right treatment.

Chronic heartburn or GERD can seriously affect one's quality of life. If you're having repeated episodes of acid reflux, consult your doctor about how to remedy the problem. Antacids, surgery or even home remedies and lifestyle changes can alleviate your symptoms.

Source:

Carol Ann Rinzler, Ken DeVault, MD. Heartburn & Reflux for Dummies. Wiley Publishing, Inc., 2004.

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