FACTORS PROTECTING THE ESOPHAGUS AGAINST ACID-MEDIATED INJURY

Reflux of gastric acid and pepsins into the lower oesophagus causes sy mptoms such as heartburn and nausea, and tissue injury leading to eros ive oesophagitis and stricture formation. This article reviews the mec hanisms involved in protecting the oesophagus against acid-mediated in jury, including the role of the lower oesophageal sphincter, secondary oesophageal peristalsis and swallowed saliva. The oesophageal mucosa has inherent abilities to resist acid damage, and recent data from thr ee laboratories suggest a secretory function with local production of bicarbonate and mucus responsive to local acidification. The evidence for these putative oesophageal defence mechanisms is discussed.