The Gastro-Intestinal Tract full anatomy

The digestive system

1. Stomach and duodenum NABIN PANDEY BOVS 7 TH batch LEIRC

2. Acknowledgement I would like to express my sincere gratitude to LEIRC for the platform. Special thanks to Prof .and Dr .Milan Sedhai for his insightful advice, encouragement and inspiring enthusiasm. I also extend my appreciation to my family and friends for their unwavering support. Lastly, I am grateful to everyone who contributed, directly or indirectly, to the completion of this work. Thank you all.

3. What we”ll discuss GI system: different parts, functions of sotamch and duodenum blood supply, nerve supply and lymphatics

4. Stomach Lies in upper abdomen, left side of your body Muscular, elastic hollow structure Divided into three regions: the fundus, body and antrum Two sphincters: cardiac sphincter and pyloric sphincter

5. Structure of the wall of stomach Four layers serosa muscularis sub mucosa mucosa

6. serosa Simple squamous epithelium known as mesothelium Produces serous fluid, which lubricates the outer wall of the stomach and ensures its smooth movement. Continuous with the parietal peritoneum

7. Muscular layer Smooth muscle, inner oblique, middle circular and outer longitudinal . Pneumonic (LOCI) Layers contract to throw the mucosa and submucosa into rugae. Presence of Auerbach's plexus( myenteric plexus) between longitudinal and circular muscle.

8. Sub mucosa Connective tissue layer Consists of Meissner’s plexus( sub mucosal plexus.

9. Mucosa Lined by simple columnar epithelium (gastric glands). consists of specialized cells ( glands) Parietal cells: secretes HCL and intrinsic factor Chief cells: pepsinogen Mucous cells: mucus secretion G cells: gastrin hormone

10. Cells of stomach secretion functions Parietal cells HCL and intrinsic factor Activate digestive enzymes and break down food particles Chief cells Pepsinogen Digest protein Mucous cells mucous Lubricates stomach lining G- cells gastrin Stimulate acid production

11. Gland type location Secretions Functions Cardiac glands Near the cardiac orifice Mucus and bicarbonates Lubricates and protects the stomach lining. Gastric glands Body and fundus of stomach HCL , pepsinogen and intrinsic factor Digest food, kill bacteria and activate digestive enzymes. Pyloric glands Pyloric region Mucus, gastrin Neutralize acid Glands of stomach

12. BLOOD SUPPLY Arterial blood is supplied by branches of coeliac artery which is a branch of abdominal aorta Venous drainage into the portal vein

13. NERVE SUPPLY Supplied by parasympathetic( excitatory) vagus nerve (CN X) Increase gastric secretion and motility Carries afferent fibers for reflexes

14. NERVE SUPPLY Supplied by sympathetic ( Inhibitory) greater splanchnic nerve celiac ganglion stomach Decrease gastric secretion and motility Constricts blood vessels to reduce gastric activity during stress Modulates pain sensation

15. Duodenum First part of small intestine . C- shaped looped around head of pancreas. Receives chyme from the stomach. Mixes with bile and pancreatic enzymes for digestion. Neutralizes acid with bicarbonate.

16. Duodenal secretion First part of small intestine . C- shaped looped around head of pancreas. Receives chyme from the stomach. Mixes with bile and pancreatic enzymes for digestion. Neutralizes acid with bicarbonate.

17. Gland type Secretions Functions Brunners gland Mucus Protects duodenal linning and neutralizes acid. Enteroendocrine gland Secretin, cholecystokinin , gastric inhibitory peptide Stimulates HC03- Release, inhibits gastric acid secretion, stimulates bile release, triggers pancreatic enzyme secretion, inhibits gastric acid secretion . Duodenal epithelial glands enterokinase Neutralize acid Glands of duodenum

18. organ Secretions Functions Stomach Chyme Provides acidic food to be further digestion. liver bile Emulsifies fat pancreas amylase, lipase, proteases Break down carbs, fats and proteins. Secretion from other oragns into duodenum

19. BLOOD SUPPLY From celiac trunk and superior mesenteric artery which are branches of abdominal aorta. Artery Source Region supplies Superior pancreatic duodenal artery Gastroduodenal artery ( from celiac trunk) Upper half Inferior pancreatic duodenal artery Superior mesenteric artery Lower half

20. Venous SUPPLY Pancreaticoduodenal vein drains into superior mesenteric vein into portal vein to liver.

21. NERVE SUPPLY Same as of stomach

22. References Chat gpt , deepseek Russ and Wilson anatomy and physiology in health Ninja nerd( youtube ) Google scholar Guyton and hall textbook of medical physiology