lower esophageal sphincter (LES)

Function

• tonic contraction of the LES contributes to prevention of gastroesophageal reflux

Pathology

• the crural portion of the diaphragm contributes to the LES pressure
• thus a hiatal hernia weakens the LES & may predispose to GERD (gastroesophageal reflux disease)
• relaxation of the LES allows food to pass with swallowing.
• transient relaxation of the LES (not associated with swallowing) is the most common cause of GERD.

More general terms

• gastrointestinal structure
• sphincter

Additional terms

• diaphragm muscle
• gastroesophageal reflux disease (GERD)
• hiatal hernia
• swallowing (deglutition)