Which factor(s) prevent(s) breakdown of the body's normal defense barriers that protect against ...

ANS: B, D
Prostaglandins play a major role in protecting the stomach walls from injury by stomach acids and enzymes. They inhibit gastric acid secretion, maintain blood flow, and stimulate mucus and bicarbonate production. Mucous cells secrete mucus that coats the stomach wall and protects the stomach wall from hydrochloric acid and the digestive enzyme pepsin. For decades, ulcer treatment focused on reducing acid secretions (anticholinergic agents, H2 antagonists, proton pump inhibitors), neutralizing acid (antacids), or coating ulcer craters to hasten healing (sucralfate). Major changes in therapy have come about because the FDA has approved antibiotics to eradicate H. pylori. Intrinsic factor is a glycoprotein secreted by parietal cells of the gastric mucosa. It has an important role in the absorption of vitamin B12 (cobalamin) in the intestine, and failure to produce or use intrinsic factor results in the condition termed pernicious anemia.