Stomach Acid

• The gastric glands that line the stomach wall secrete an acidic solution that creates a low pH environment within the stomach
• The normal pH of the stomach is ~1.5-2.0, which is optimal for hydrolysis reactions
• Acid conditions: assist in the digestion of food, activate stomach proteases, prevent pathogenic infection
• The stomach wall is lined by a layer of mucus protecting the stomach lining
• The pancreas releases bicarbonate ions into the duodenum to neutralize the stomach pH
• The low pH environment of the stomach is maintained by proton pumps in the parietal cells of the gastric pits
• Proton pumps secrete H+ ions (via active transport) which combine with Cl– ions to form hydrochloric acid
• Proton pump inhibitors (PPIs) are drugs which irreversibly bind to the proton pumps and prevent H+ ion secretion
• PPIs are used to prevent gastric discomfort caused by high acidity
• • Individuals taking PPIs may have increased susceptibility to gastric infections due to the reduction of acid secretion