1. 3.5 Digestion in the Small and Large Intestines Pages 185-188

2. Small intestine Site of digestion of carbohydrates, lipids and protein Food passes through in 3-5 hours

3. Dimensions of Small Intestine Diameter 2.5 cm 7 m long

4. Sections

5. Duodenum First section 25-30 cm Digestive enzymes added Acid is neutralized Secretions from the liver and pancreas enter the duodenum through a common duct

6. Jejunum Digestion and absorption

7. ileum absorption

8. Chemical Digestion Pyloric sphincter regulates movement of chyme into the small intestine

9. Chyme Water Food Digestive enzymes

10. Pancreas Produces: 1)digestive enzymes which pass through pancreatic duct. Lipase fat  glycerol and fatty acids pancreatic amylase Trypsin 2) insulin

11. Pancreas Produces sodium bicarbonate which increases the pH of chyme from pH 2.5 to pH 9.

12. Small Intestine Secretes maltase maltose  glucose Peptidases, in the small intestine, complete the digestion of protein

13. Cholesystokinin, CCK, from duodenum lining prompts pancreas to secrete…

14. Secretin Prosecretin  secretin acid Functions- stimulates liver to secrete bile - stimulates pancreas to secrete enzymes -stimulates pancreas to secrete HCO 3 - - change in pH inactivates pepsin -regulates rate

15. trypsinogen enterokinase trypsinogen  trypsin Further digests long-chain protein into short- chain protein Enzmes: carboxypeptidase and erepsin break protein segments down into amino acids

16. Fats Too big for enzyme lipase Bile emulsifies fats…micelles

17. Liver Mass is 1.5 kg Liver detoxifies blood, Glycogen manufacture and storage, vitamins Produces bile

18. Bile Bile contains bile salts that help to emulsify fats. Large fat molecules globules are broken down into tiny globules. Bile is made in the liver and stored in the gall bladder

19. Villi and microvilli Finger-like projections increase the surface area for absorption

20. Where the food goes Sugars, amino acids, water-soluble vitamins and minerals go into capillaries Fats go into lacteal  lymphatic system  bloodstream

21. Large intestine 1.5 m in length 7.6 cm diameter Cecum, colon, rectum and anus Colon: ascending  transverse  descending  sigmoid Rectum: last 20 cm

22. Functions of large intestine Absorbs water (20L per day) Vitamins B and K, and Na + and Cl - 4-72 hours 500 species of bacteria (gas)

23. Cellulose and Fibre Bulk Full-feeling lasts longer

24. Anus Defecation reflex-eliminated feces 1 st sphincter, the internal anal sphincter is a smooth muscle (involuntary) 2 nd sphincter, the external anal sphincter is made of skeletal muscle and is voluntary Both muscles must be relaxed for defecation to happen