RT Book, Section A1 Kasper, Dennis L. A1 Fauci, Anthony S. A1 Hauser, Stephen L. A1 Longo, Dan L. A1 Jameson, J. Larry A1 Loscalzo, Joseph SR Print(0) ID 1128786853 T1 Peptic Ulcer and Related Disorders T2 Harrison's Manual of Medicine, 19e YR 2016 FD 2016 PB McGraw-Hill Education PP New York, NY SN 9780071828529 LK accessmedicine.mhmedical.com/content.aspx?aid=1128786853 RD 2024/04/19 AB Peptic ulcer disease (PUD) occurs most commonly in duodenal bulb (duodenal ulcer, DU) and stomach (gastric ulcer, GU). It may also occur in esophagus, pyloric channel, duodenal loop, jejunum, and Meckel’s diverticulum. PUD results when “aggressive” factors (gastric acid, pepsin) overwhelm “defensive” factors involved in mucosal resistance (gastric mucus, bicarbonate, microcirculation, prostaglandins, mucosal “barrier”) and from effects of Helicobacter pylori.