Gastric-mucosal protection
  • Gastric epithelium is liable to be attcked by acid and gastric enzymes but it is protected by a thick alkaline mucus that is secreted by the surface epithelium.

  • protective barrier between the epithelium and the acid and pepsin in the gastric lumen

  • mucus is heavily glycosylated to protect it from proteolysis by pepsin

  • mucus layer is also buffered by HCO3 secreted by the epithelial cells that produces a protective pH gradient across the mucus layer