Gastric Pits

• The stomach wall is lined with millions of gastric pits that release gastric juice into the stomach lumen
• Gastric juice is an acidic solution that breaks down food into a creamy paste called chyme
• The gastric pits are lined by different cell types that contribute to the stomach's function: goblet cells, parietal cells, G cells, D cells, and Chief cells
• Goblet cells – secrete mucus to form a protective layer around the stomach lining
• Parietal cells – secrete hydrochloric acid which is responsible for creating a low pH environment in the stomach
• G cells – secrete gastrin (stimulates release of stomach acids to increase stomach acidity)
• D cells – secrete somatostatin (inhibits release of stomach acids to reduce stomach acidity)
• Chief cells – secrete pepsinogen (inactive protease precursor which is activated by acidity to form active pepsin)