Lesson 19 - Gastric Secretions PDF

Lesson 19 Gastric Secretions 3° Medicine Professor: Vittoria Carrabs PhD Academic year: 2024/25 INDEX 1. Gastric secretions 2. Regulation of acid secretion by parietal cells Main mediators HISTAMINE paracrine GASTRIN endocrine ACETYLCHOLINE...

Lesson 19 Gastric Secretions 3° Medicine Professor: Vittoria Carrabs PhD Academic year: 2024/25 INDEX 1. Gastric secretions 2. Regulation of acid secretion by parietal cells Main mediators HISTAMINE paracrine GASTRIN endocrine ACETYLCHOLINE PGE2, PGI2 SOMATOSTATIN 3. Drugs used to inhibit or neutralise acid gastric secrection HISTAMINE RECEPTOR ANTAGONISTS PROTON PUMP INHIBITORS, ANTIACIDS TREATMENT OF H. PYLORI 4. Drugs that protect the mucosa.  1. GASTRIC SECRETION The stomach is a muscular reservoir where food enters after being swallowed. Gastric juices are the first major source of digestive capacity. The stomach’s digestive functions are not essential for the assimilation of a mixed meal, and surgical removal of almost the entire stomach generally allows for adequate nutrition. Some degree of gastric secretory function is required for the absorption of an essential vitamin, B12, and gastric acid may also be important for the absorption of dietary iron. Additionally, gastric secretions help sterilize food. 1. GASTRIC SECRETION  1. GASTRIC SECRETION The stomach secretes various substances that aid in digestion and protect the stomach lining. Hydrochloric Acid (HCl): Produced by parietal cells, creates an acidic environment that helps in the initial breakdown of food AGRESSIVE FACTORS through simple hydrolysis and has antimicrobial properties. Gastric acid Pepsinogen: Secreted by chief cells, is an inactive precursor that Proteolytic enzymes is converted to the active enzyme pepsin in the acidic environment Irritant substances of the stomach. Pepsin is crucial for protein digestion. (alcohol, cafeine, NSAIDs) Bilis Intrinsic Factor: Also produced by parietal cells, essential for the Bacteria toxins absorption of vitamin B12 (cobalamin) in the distal parts of the intestine. PROTECTIVE FACTORS Mucus: Secreted by mucous cells lining the stomach, mucus Mucus forms a protective layer. HCO3- PGs Lipase: Produced by chief cells, gastric lipase contributes to the initial digestion of triglycerides  2. REGULATION OF ACID SECRETION BY PARIETAL CELLS Disturbances of acid secretion are important in the pathogenesis of peptic ulcer. Parietal cells secretion: pH