If a person is suffering from GERD what malfunctioning?

In Gastroesophageal reflux disease (GERD), the malfunction lies in the lower esophageal sphincter (LES), which fails to function properly as a one-way valve between the stomach and the esophagus. The LES is a circular muscle that normally opens to allow food and drink to pass into the stomach and then closes to prevent the backflow of stomach contents into the esophagus.

In individuals with GERD, the LES is either weakened or relaxes inappropriately, causing stomach acid and other contents to leak back into the esophagus. Acid from the stomach irritates the lining of the esophagus, sometimes extending over long periods due to repeated backflow, contributing to the spectrum of symptoms and associated problems that come with this condition.