Lower esophageal sphincter

Definition

The lower esophageal sphincter (LES) is a muscular ring at the junction between the esophagus and stomach. It prevents the backflow of stomach contents into the esophagus.

5 Must Know Facts For Your Next Test

1. The LES is crucial in preventing gastroesophageal reflux disease (GERD).
2. It relaxes to allow food to enter the stomach and contracts to prevent acid reflux.
3. Dysfunction of the LES can lead to conditions such as heartburn and Barrett's esophagus.
4. Certain medications, like anticholinergics, can affect the tone of the LES.
5. Lifestyle factors such as obesity, smoking, and diet can influence LES function.

Review Questions

• What is the primary function of the lower esophageal sphincter?
• How does dysfunction of the LES contribute to GERD?
• Name two lifestyle factors that can affect LES function.

Related terms

Gastroesophageal Reflux Disease (GERD): A chronic condition where stomach acid frequently flows back into the esophagus.

Barrett's Esophagus: A condition where prolonged acid exposure leads to changes in the cells lining the lower esophagus.

Anticholinergics: A class of drugs that block acetylcholine in the nervous system, which can impact various bodily functions including LES tone.