What is gastroesophageal sphincter?

The gastroesophageal sphincter, also known as the lower esophageal sphincter (LES), is a ring of muscle located at the junction of the esophagus and the stomach. Its primary function is to prevent the backflow of stomach contents, including acid, into the esophagus, thereby protecting the esophageal lining from irritation and damage. Proper functioning of the LES is crucial in preventing conditions such as gastroesophageal reflux disease (GERD). Dysfunction of this sphincter can lead to symptoms like heartburn and regurgitation.