The Anatomy and physiology of stomach .pptx

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1. Anatomy and physiology of stomach Dr.Roshan Kumar 1st year post graduate

2. Anatomy of stomach The stomach contains four anatomic regions 1.Fundus 2.Cardia 3.Body 4. Antrum

3. Anatomy of stomach Arterial Supply ♦ Left gastric artery, a branch of coeliac artery (Smallest branch of coeliac axis). ♦ Right gastric artery, a branch of hepatic artery. ♦ Gastroduodenal artery, a (largest) branch of hepatic artery. ♦ Right gastroepiploic artery, a branch of gastro duo denal artery. ♦ Left gastroepiploic artery, a branch of splenic artery. ♦ Short gastric arteries, branches of splenic artery.

4. Anatomy of stomach Venous Drainage ♦ Right and left gastric veins drain into portal vein. ♦ Right gastroepiploic vein drains into superior mesenteric vein. ♦ Left gastroepiploic vein and short gastric veins drain into splenic vein. ♦ Prepyloric vein of Mayo distinguishes pyloric canal from first part of duodenum

5. Anatomy of stomach NERVE SUPPLY OF STOMACH ♦ Intrinsic innervation occurs through myenteric plexus of Auerbach and submucous plexus of Meissner. ♦ Right vagus is posterior and left vagus is anterior.

6. Anatomy of stomach ♦ Posterior vagus gives criminal nerves of Grassi, which supply lower oesophagus and fundus of stomach, which, if not cut properly during vago tomy, may lead to recur- rent ulcer. ♦ Vagus also gives splanchnic branches (hepatic and coeliac branches), ends as nerve of Latarjet which sup plies the antrum and maintains the antral pump. ♦ Parietal branches help in HCl secretion, which is an impor- tant concept in vagotomy that is done as a treatment in duodenal ulcer. ♦ Truncal vagotomy with posterior gastrojejunostomy is done for chronic duodenal ulcer with pyloric stenosis.

7. Highly selective vagotomy (HSV) is done in case of uncom - plicated chronic duodenal ulcer which is not responding to available medical line of treatment. In HSV, nerve of Latarjet is retained so as to retain antral pump and no drainage is required. Here only the fi bres entering the stomach are ligated close to the lesser curve to reduce the acid secretion. ♦ In selective vagotomy splanchnic branches are retained but it is presently not done. ♦ Gastroduodenal pain is sensed via sympathetic fibres (T5-T10).

8. Lymphatic drainage of stomach

9. Lymphatics of proximal half of stomach drain into left gastric, splenic, and superior pancreatic lymph nodes. From antrum, it drains into right gastric, right gastroepiploic, and subpyloric lymph nodes. From pylorus, it drains into right gastric and subpyloric lymph nodes. ♦ Efferent lymphatics from suprapyloric region drain into para-aortic lymph nodes and so into left supraclavicular lymph nodes. Efferent lymphatics from subpyloric lymph nodes drain into superior mesenteric lymph nodes. Lymphatics near oesophagogastric (OG) junction commu - nicate with oesophageal lymphatics. ♦ In carcinoma stomach if upper lymphatics are blocked, retrograde spread through lower lymphatics can occur

10. HISTOLOGY ♦ The fundus and body contains parietal and chief cells. ♦ Parietal cells secrete acid and intrinsic factor. ♦ Chief cells produce pepsinogen. There are two types of pepsinogen secreted by chief cells—I and II. Pepsinogen I is produced only in stomach. In gastric atrophy pepsinogen I is decreased. ♦ In the antrum, endocrine cells produce gastrin (G cells) and somatostatin (D cells). ♦ 12% of epithelial cells of stomach are parietal (oxyntic) cells; 45% chief (zymogenic cells); 40% mucous cells; 3% endocrine cells. ♦ Pyloric sphincter is a thick circumferential layer of smooth muscle