ESOPHAGEAL DEFENSE-MECHANISMS

Various defence mechanisms are found in the oesophagus which can be el icited by reflux damage. Premucosal defence includes bicarbonate ions and epidermal growth factor (EGF) secreted by salivary and oesophageal glands. The mucosa can respond by increasing epithelial cell turnover and upregulating EGF receptor and endocytosis. The intercellular barr ier can be increased by the contents of membrane-coating granules. Loc al pH can be regulated by carbonic anhydrase. The whole viscus can exh ibit peristalsis to effect a mechanical clearance of the refluxed gast ric and duodenal material.