The document summarizes the physiology of the stomach and duodenum. It describes the anatomy, blood supply, nerve supply, and functions of the stomach, including gastric secretion, motility, and emptying. It also discusses gastric glands, cells, phases of gastric secretion, and regulation. For the duodenum, it covers anatomy, blood supply, lymphatic drainage, functions, duodenal glands and secretions. It briefly mentions common disorders of the stomach and duodenum such as gastritis, ulcers, motility disorders, and duodenitis.

1. PHYSIOLOGY OF
STOMACH
&
DUODENUM
DR SAPAN KUMAR
1ST YEAR PG
GENERAL SURGERY
MKCG

2. PHYSIOLOGY OF STOMACH
1. Quick Anatomy of Stomach
2. Physiology of Stomach
Function of Stomach
Gastric secretion- Glands, Composition, Regulation, Phases
GI motility & gastric emptying
Peistalsis
Gastrointestinal hormones
Disorder of stomach

3. ANATOMY OF STOMACH
• Stomach is the most dilated part of the gastrointestinal tract
• It lies upper left quadrant of abdominal cavity, occupying the epigastric, umbilical & left
hypochondriac region.
• J shaped (vertical)
• Obese persion- horizontal
• Length- 25cms
• Capacity- 1.5 to 2 Ltr

4. ANATOMY OF STOMACH
• It has 4 parts-
• Cardia
• Fundus
• Body
• Antrum
• Pylorus

5. ANATOMY OF STOMACH
2 Curvatures
• Greater curvature
• Lesser curvature
2 Surfaces
• Anterosuperior surface
• Posteroinferior surface

6. ANATOMY OF STOMACH
RELATIONS OF STOMACH
ANTERIOR- Liver
Diaphragm
Transverse colon
Anterior abdominal wall
POSTERIOR- Diaphragm Splenic flexure of colon
Left kidney Pancrease Splenic artery
Left suprarenal gland Transverse mesocolon

7. BLOOD SUPPLY OF STOMACH
LESSER CURVATURE
• LEFT GASTRIC ARTERY (COELIAC TRUNK)
• RIGHT GASTRIC ARTERY (HEPATIC ARTERY)
GREATER CURVATURE
• LEFT GASTROEPIPLOIC ARTERY (SPLENIC ARTERY)
• RIGHT GASTROEPIPLOIC ARTERY (GASTRODUODENAL ARTERY)
FUNDUS
• SHORT GASTRIC ARTERY (SPLENIC ARTERY)

8. NERVE SUPPLY OF STOMACH
SYMPATHETIC
T6 to T10 spinal segments
• Motor to pyloric sphincter
• Carry pain sensation from stomach
PARASYMPATHETIC
Vagus nerve & its branches
• Gasric motility
• Gastric secretion

9. LYMPHATIC DRAINAGE OF STOMACH
A- pancreatico-splenic nodes
B- right gastroepiploic nodes
C- left gastric nodes
D- pyloric nodes
All ultimately drains into Coeliac nodes.
A
B
C
D

10. PHYSIOLOGY OF STOMACH
FUNCTION OF THE STOMACH
Storage of food until it is processed
Mixing of food with gastric secretion and forms a semisolid micture called Chyme.
Slow emptying of chyme from stomach into small intestine at a suitable rate for better
digestion and absorption.

12. GASTRIC GLANDS
Gastric glands are located beneath the gastric pits within gastric mucosa.
Gastric glands are named according to their location.
• Cardiac glands- found in cardia of stomach
• Fundic glands- found in fundus of stomach
• Pyloric glands- located in antrum & pylorus

13. GASTRIC CELLS
• Mucus cell
• Parietal cell
• Chief cell
• Enterochromafin cell

14. PARIETAL CELL
• Present only in fundus of stomach
• Secrete HCL & intrinsic factor
• INTRINSIC FACTOR- required for absorption of vitamin B12
• HCL- main component of gastric juice
Kills micro organism present in food
Activate pepsinogen(inactive) to Pepsin(active) required for protein breakdown & digestion.

15. CHIEF CELL
• Present only in fundus
• Secrete PEPSINOGEN- inactive form of pepsin,
required for protein breakdown & digestion.

17. COMPOSITION OF GASTRIC JUICE
• Approx secretion of gastric juice is 1.5 – 2 ltr per day
• When meal is consumed, it stimulates release of gastric juice from gastric glands.
HCL Pepsin
Sodium intrinsic factor
potassium gastric lipase
bicarbonate
Gastric Juice
water solutes
Inorganic Organic

18. GASTRIC ACID SECRETION

19. PHASES OF GASTRIC SECRETION
• Cephalic phase
• Gastric phase
• Intestinal phase

20. CEPHALIC PHASE
• It occurs even before food enters the stomach
• It results from sight, smell, thought of food.
• It accounts for 30% of gastric secretion.
• Neurogenic signal transmit through vagus nerve (dorsal motor nuclei).

21. GASTRIC PHASE
• Once food enters the stomach, it excites local enteric reflex, gastrin mechanism, which
causes stimulation of gasric juice secretion.
• It accounts for 60% of gastric secretion.

22. INTESTINAL PHASE
• Presence of food in duodenum or upper part of small intestine , stimulate stomach to
secrete small amount of gastric juice.
• This is due to relase of gastrin in duodenal mucosa.
• It accounts of 10% of gastric secretion.

23. REGULATION OF GASTRIC ACID SECRETION
• Stimulated by – acetylcholine, gastrin, histamine.
• Inhibited by- presence of food in small intestine.
presence of acid, fat, protein breakdown product.
secretin.
gastric inhibitory peptides
VIP
somatostatin

24. GI MOTILITY & GI EMPTYING
• When food enters stomach the fundus and upper part of body relax and accommodate the
food.
• Peristalsis begins in the lower portion of body, mixing and grinding the food and
permitting chyme pass through pylorus and enter the duodenum.
• In regulation of gastric emptying the antrum, pylorus, upper duodenum function as unit.
• Contraction of antrum is followed by sequential contraction of the pyloric region and
duodenum.

25. REGULATION OF GASTRIC MOTILITY &
EMPTYING
• The rate at which the stomach empties into duodenum depends on the type of food
ingested.
• Food rich in carbohydrate empties fast
• Protein rich food leaves slowly.
• And fat containing food leaves stomach very slowly.
• The rate of emptying also depends on osmotic pressure of the chyme.
• CCK is also an inhibitor of gastric emptying.

26. PERISTALSIS
• Peristalsis is the radial symmetrical contraction and relaxation of muscles that propagates
in a wave down the tube, in anterograde direction.
• In stomach the co ordinated contraction of circular & longitudinal muscle result in
movement of chyme in forward direction.
• Presence of food in stomach result in gastric secretion and peristalsis.
• In order to stop or decrease the peristalsis (during OT), we need to decompress the
stomach with ryle’s tube.

27. PACEMAKER FOR GASTRIC PERISTALSIS
• The source of myogenic activity in GIT has been tracked down to INTERSTITIAL
CELLS OF CAJAL, which act as pacemaker, that generates slow wave in smooth muscle.

28. INTERSTITIAL CELL OF CAJAL
• These are the type of interstitial cell found in GIT.
• Myenteric interstitial cell of cajal (ICC MY) serve as a pacemaker bioelectrical slow wave
potential that leads to contraction of smooth muscle.
• These contraction of smooth muscle result in peristalsis.

29. GASTROINTESTINAL HORMONES

30. ACHLORHYDRIA
• Failur of stomach to secrete HCL, despite maximum stimulation.
• It also prevent the function of pepsin.

31. GASTRIC ATROPHY
• Normally gastric secretion contains Intrinsic factors.
• In case of atrophy there is reduced intrinsic factors.
• Results in decrease absorption of vitamin B12 in ileum.
• This may lead to pernicious anemia.

32. GASTRITIS
• Inflammation of gastric mucosa.
• May be associated with H. Pylori
• Upper abdominal pain, nausea, vomiting, indigestion, heart burn.
• Diagnosis can be done by endoscopy + biopsy
• Rx antibiotic, PPI

33. GASTRIC ULCER
• Break in the inner lining of stomach..
• Due to H. Pylori infection or NSAIDS.
• Presented with upper abdominal pain and dyspepsia.
• Dx by upper GI endoscopy + biopsy.
• Rx antibiotic, PPI

34. MOTILITY DISORDER
• Gastroesophageal reflux disorder
• Achalasia cardia

35. GERD
• It’s a type motility disorder due to malfunction of lower esophageal sphincter.
• It cause backflow of stomach content & acid into esophagus. That irritate and damage the
esophageal lining.
• Pt may experience nausea, heartburn, regurgitation, bitter taste, dry cough.
• Diagnosis by Upper GI endoscopy.
• Complications- esophagitis, esophageal stricture, barrett’s esophagus.
• Treatment includes – Antacids, PPI

36. SURGICAL TREATMENT OF GERD
• Fundoplication – wrapping the top of stomach around lower esophageal sphincter, thus
prevent reflux.
• LINX DEVICE- ring of magnetic beads wrapped around the junction of stomach &
esophagus. The magnetic attraction between the beads is strong enough to prevent acid
reflux, but weak enough to allow food.

39. ACHALASIA CARDIA
• Due to failure of lower esophageal sphincter to relax.
• Difficulty for food to pass down to stomach
• People may complain of heart burn, regurgitation, difficulty in swallowing.
• Diagonsis by barium swallow, esophageal manometry,
endoscopy
• Treatment – esophageal dilatation, myotomy.

40. PHYSIOLOGY OF DUODENUM
• Quick anatomy of duodenum.
• Physiology of duodenum
function of duodenum
Duodenal Glands & Scecretion
Disorder of Duodenum

41. ANATOMY OF DUODENUM
• Duodenum is the first portion of small intestine.
• C shaped. 10-15 inch
• It has four parts-
1st part / superior part (L1)
2nd part / descending part( L3)
3rd part / horizontal part
4th part / ascending part (L3)

42. BLOOD SUPPLY OF DUODENUM
• Proximal to 2nd part- Gastroduodenal A & Superior Pancreaticoduodenal A
• Distal- superior mesenteric A & Inferior Panceraticoduodenal A

43. LYMPHATIC DRAINAGE OF DUODENUM
• Anterior - Panceaticodudenal lymphnode, pyloric lymphnode
• Posterior- superior mesenteric lymphnode,

44. PHYSIOLOGY OF DUODENUM
• Duodenum is lined by mucus secreting columnar epithelium.
• Endocrine cells in duodenum produce CCK & secretin in response to acid and fatty food.
• These inhibit gastric acid secretion.

45. FUNCTION OF DUODENUM
• Gate controller of food from stomach to jejunum.
• This is the first site of contact for gastric secretion, bile, digestive enzymes from gall
bladder and pancreas.
• Play important role in digestion and absorption of nutrients.

46. DUODENAL GLANDS & SECRETION
BRUNNER’S GLAND
Found only in duodenenal submucosa.
It produce mucus (bicarbonate rich)
Protect duodenum from acidic content of chyme.
Provide alkaline medium for activation of intestinal enzyme
Lubricate the intestine.

47. DUODENITIS
• Inflammation of duodenal mucosa
• May be due to
H. pylori
bacterial infection
NSAIDS
Autoimmune (Crohn’s disease)
Dx by endoscopy + biopsy
RX antibiotics, PPI

48. DUODENAL ULCER
• Ulcer due to infection by H.pylori.
• This bacteria erodes the protective barrier of duodenal mucosa, predisposing it to damage
by gastric acids.
• Pt presented with upper abdominal pain & dyspepsia.
• Diagnosis by Endoscopy + biopsy
• Managed by antibiotics, PPI, Antacids.