Lower esophageal sphincter

Definition

The Lower Esophageal Sphincter is a ring-like muscle at the bottom of the esophagus that acts as a valve, opening to allow food and liquid to enter the stomach and closing to prevent stomach contents from refluxing back into the esophagus. It plays a crucial role in the digestive process by controlling the flow of food and protecting the esophagus from acidic gastric contents.

Related terms

Esophagus: A muscular tube that connects the throat (pharynx) with the stomach; it transports swallowed food and liquids.

Gastroesophageal Reflux Disease (GERD): A digestive disorder that occurs when acidic stomach juices, or food and fluids back up from the stomach into the esophagus due to a weak or relaxed LES.

Peristalsis: Coordinated, rhythmic contractions of smooth muscle that move food through the digestive tract, including down the esophagus toward the stomach