Orlando Roy C. M.D.Journal of Clinical Gastroenterology: June 1986 Original Article: PDF Only Buy Abstract Tissue resistance is an important esophageal defense mechanism against acid-peptic injury from reflux. This is shown by the ability of esophageal epithelium to avoid injury despite low luminal pH for considerable periods. Tissue resistance, however, is not a single factor but a group of complex processes intimately associated with the epithelium that act in concert to provide protection. Mucus, the unstirred water layer, the epithelium proper, and its blood supply are some of the known components of this mechanism. A better understanding of the epithelium and its defenses should provide additional insights into the pathophysiology of reflux esophagitis and alternative treatments. © Lippincott-Raven Publishers.