1. Secretion of digestive juices
Introduction to alimentary glands
Saliva
Gastric secretions
Pancreatic secretions
Bile (Biochemistry)
Secretions of small intestine
Secretions of large intestine

2. Secretion of digestive juices
Introduction to alimentary glands
Saliva
Gastric secretions
Pancreatic secretions
Bile
Secretions of small intestine
Secretions of large intestine

3. Secretions of small intestine

4. Small intestine absorptive surface
1 cm
Valvulae Conniventis
1 mm
1μm

5. Villi projecting from small intestine mucosa

6. A single villus

7. Mucous membrane on small intestine (Numerous villi on a circular fold)

8. Secretion of mucus in Duodenum
Brunner’s Glands (Duodenal glands)
Compound mucus glands
First few cm of duodenum (Duodenal cap or bulb)
Alkaline
Stimulus:
Tactile
Irritation
Vagal stimulation
Secretin
Inhibited by Sympathetic stimulation → unprotected → ulcer

9. Functions of mucus secreted by Brunner’s glands
Protect the duodenal wall from highly acidic gastric juice
It contains Bicarbonate
Neutralize acid pH of stomach
Optimum pH for pancreatic enzymes
Blockage of digestive action of digestive enzymes of stomach (because digestive enzymes of stomach become inactivated at pH>3-4.5
Holds immunoglobulins in place

10. Characteristics of secretions of small intestine
Enterocytes covering the villi contain enzymes
Digestion during absorption
For digestion of proteins
Peptidases
For digestion of carbohydrates
Sucrase, maltase, isomaltase, lactase
For digestion of fats
Intestinal lipase
Ph= 7.5-8
1800 ml/day
Composition
Water (For Hydrolysis, for digestion)
Mucus
Electrolytes
Na, Cl, HCO3
Enzymes
No enzymes

11. Question 3 sources of Mucus in small intestine
Surface epithelial cells
Brunners glands
Goblet cells

12. Regulation of small intestinal secretions
Local enteric nervous reflexes
Tactile stimuli
Irritative stimuli

13. Disorders of small intestine
Peptic ulcer
Malabsorption
Diarrhea

14. Peptic Ulcer Gastric Ulcer Duodenal Ulcer Definition:
An excoriated area of stomach or intestine principally caused by the digestive action of gastric juice or upper small intestine
Frequent site: within few cm of Pylorus

15. Causes of Peptic Ulcer Imbalance between
Rate of secretion of gastric juice
Degree of protection by
Gastroduodenal mucosal barrier
Neutralization of gastric acid by
duodenal juices
Pancreatic secretions
Bile

17. H. Pylori appear on silver staining as small, curved rods on the surface of Gastric mucosa

18. H. Pylori

19. Predisposing factors of Gastric Ulceration
Psychic disturbances (↑ acid secretion)
Smoking ( Nervous stimulation of gastric secretions)
Alcohol ( Break down the Mucosal Barrier)
Aspirin etc. ( Break down the Mucosal Barrier)

20. Physiology of Treatment of Peptic Ulcer
Antibiotics
Acid-suppressant drugs
Antacids
Treat and remove the cause
Surgical

21. Complications of Peptic Ulcer
Stricture
Perforation
Bleeding
Treatment:
Surgical

22. Malabsorption Damage to < 50% of small intestine
Intestinal adaptation
Hypertrophy and hyperplasia
Damage to > 50% of small intestine
Malabsorption

23. MCQ: Peptic ulceration tends to heal after all of the following EXCEPT:
A. Aspirin therapy
B. Division of the vagal nerve supply to the stomach
C. Proton pump inhibitors
D. Surgical removal of the pyloric antrum
E. Treatment with histamine H2 blocking drugs A

24. MCQ: Intestinal secretions contain enzymes which
A. activate pancreatic proteolytic enzymes
B. are released when the vagus nerve is stimulated
C. digest cellulose
D. hydrolyze disaccharides
E. hydrolyze monosaccharides A

25. A. acting as a protective barrier for intestinal epithelium
MCQ: The intestinal brush border promotes digestion by all of the following mechanisms EXCEPT:
A. acting as a protective barrier for intestinal epithelium
B. facilitating movement of intestinal contents
C. increasing the surface area of intestinal mucosa
D. supplying digestive enzymes
E. supplying specialized transport system B

26. MCQ: With regards to secretions of small intestine
A. Daily secretion is about 800 ml/day
B. Sodium is added to secretions ay active transport
C. Epithelial cells in villi secrete water and electrolytes
D. Digestive enzymes are mainly intracellular
E. ph is about D

27. MCQ: Crypts of Lieberkϋhan
A. Are complex glands present throughout small intestine
B. Are present throughout small and large intestine except duodenum
C. Are separated by villi
D. Contain both Goblet cells and enterocytes
E. Secrete digestive enzymes for final digestion of food D