Pepsin production is a normal physiologic activity of the stomach that, in conditions of stress, may overwhelm the stomach's weakened defenses and result in gastric ulceration. Gastric acid production is another condition that may increase and cause acute ulceration. Fuhermore, these two factors may remain unchanged and still result in gastric ulcers if the gastric defenses are weakened by stress. All of the other choices represent normal defensive forces in the stomach. Increased bicarbonate transpo would protect the gastric epithelium from the potentially harmful acidity of the gastric contents. The adherent mucus is relatively alkaline, providing local protection to the superficial mucosa. Gastric epithelial cells can normally replicate rapidly, allowing mucosal defects to be rapidly repaired. Increasing the regenerative capacity of the epithelium would have a protective effect against ulceration. The gastric mucosa is richly supplied with blood, providing the epithelial cells with an ample supply of nutrients, oxygen, and bicarbonate to contend with the harsh gastric microenvironment. Stress ulcers are associated with compromised gastric blood flow, not increased flow. Ref: Mills J.C., Stappenbeck T.S., Bunnett N. (2010). Chapter 13. Gastrointestinal Disease. In S.J. McPhee, G.D. Hammer (Eds), Pathophysiology of Disease, 6e.