gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) refers to a clinical syndrome characterized mainly by heartburn and acid regurgitation caused by reflux of gastric and duodenal contents into the esophagus. Generally, the stomach stores gastric acid, and the duodenal lumen contains bile fluid; these are digestive juices that can digest ingested meat or other foods. The stomach is naturally protected by a mucosal barrier like a porcelain layer, so gastric acid is safe in the stomach. When eating, a large amount of gastric acid is secreted to digest food in the stomach cavity, and after being neutralized, the gastric contents pass into the duodenum where they are further digested by bile until, after absorption in the small intestine, the residue becomes feces and is excreted. If gastric fluid refluxes into the esophageal lumen, the esophagus lacks a porcelain-like mucosal protective layer, and gastric acid will erode and destroy the esophageal mucosa, causing erosion and ulcers.