1. …the small & large intestines 9.5
Digestion in…
…the small & large intestines
9.5

2. Small Intestine about 2.5 cm in diameter up to 7 m in length
duodenum: first cm: digestion
jejunum: digestion/ absorption
ileum: absorption
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3. Accessory Organs
Liver, pancreas, gall bladder

4. pH of Small Intestine chyme has pH of about 2.5
prosecretin converts into secretin, which causes pancreas to release bicarbonate ions (increasing pH to 9.0)
pepsin is inactivated in basic conditions, thus secretin protects the small intestine
(secretin also stimulates liver to produce bile, and pancreas to release enzymes)

5. Pancreatic Secretions
chyme enters duodenum
cholecystokinin (CCK) is released into blood by cells in duodenum
CCK causes pancreatic cells to release various substances

6. Carbohydrate Digestion
pancreatic amylase is released into duodenum
continues breakdown of starch started in the saliva

7. Protein Digestion trypsinogen released by pancreas
activated to trypsin by enzyme enterokinase
trypsin continues to break down proteins
carboxypeptidase & erepsin break down small chains into single amino acids

8. Lipid Digestion
bile is produced in liver & stored in gall bladder and released into the duodenum
bile breaks down large fat globules
lipases secreted by pancreas break down fats into smaller molecules
digested fats are absorbed through lacteals

9. Small Intestine - Absorption
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Villi and microvilli increase the surface area for absorption of nutrients.

10. Absorption passive transport (including osmosis) facilitated diffusion
active transport
nutrients are absorbed in capillary networks
Passive transport is the movement of materials across a cell membrane without the use of energy from the cell. (move from high concentration to low concentration)
Facilitated diffusion is the diffusion of molecules across a membrane through transport proteins (embedded in the cell membrane and help diffusion).
Active transport is the movement of materials across a cell membrane using energy from the cell (move from lower concentration to higher concentration)

11. Large Intestine up to 7.6 cm in diameter about 1.5 m in length
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12. Large Intestine most of the water is absorbed
500+ species of bacteria produce essential vitamins K and some B.
feces (soft solid) are egested through the anus

13. Resources…
McGraw-Hill Ryerson animation & quiz (good overview, but not a lot of detail about the enzymes & secretions)
Another McGraw-Hill digestion quiz

14. Let’s review…

15. Image from: http://www.merriam-webster.com/art/med/digestio.htm

16. Review…
These quizzes are good for reviewing anatomy, but not the enzymes/secretions:

17. And finally…science meets art
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Belgian conceptual artist Wim Delvoye created a machine that digests food…and produces feces.