1. Digestive System & Diet
SBI 3U
9.5

2. The Pancreas https://www.youtube.com/watch?v=NZ4zcrTzUjA
Produces digestive juices through the pancreatic duct to the duodenum.
Produces enzymes that digest carbohydrates (amylase), proteins (Trypsin) and fats (Lipase).
Produces bicarbonate salts to neutralize the stomach acid.
The pancreas is also an endocrine organ that produces insulin and glycogen to help in the metabolism of sugar

3. http://www. emc. maricopa. edu/faculty/farabee/biobk/BioBookDIGEST

4. Liver

5. Liver… Largest internal organ
Produces Bile. Bile emulsifies fats to break them into tiny droplets called micelles
Liver continuously produce Bile and store them in the gall bladder
All blood traveling through the capillary beds of the intestine, enter the liver before returning to the heart
Liver remove toxins such as alcohol , produce and store glycogen and fat soluble vitamins
Disease: hepatitis, jaundice, cancer

6. Gall bladder Lies under the liver Stores bile – a greenish liquid
When lipid enter the duodenum, the gall bladder will contract and secrete bile to emulsify fats.
Has a common duct with the pancreas

7. Small Intestine
The small intestine is where final digestion and absorption occur. The small intestine is a coiled tube can be up to 7 meters long. Coils and folding plus villi give this tube the surface area of a m long tube. Final digestion of proteins and carbohydrates must occur, and fats have not yet been digested. Villi have cells that produce intestinal enzymes which complete the digestion of peptides and sugars.

8. Small intestine
The absorption process also occurs in the small intestine. Food has been broken down into particles small enough to pass into the small intestine. Sugars and amino acids go into the bloodstream via capillaries in each villus. Glycerol and fatty acids pass through the lacteals (lymphatic vessels within a Villus) to the bloodstream. Absorption is an active transport, requiring cellular energy.

9. Small intestine continued
Has an increased surface area due to fingerlike projections called VILLI
Produces enzymes that complete the digestion of carbohydrates, proteins and fats.
Consists of 3 areas
Duodenum
Jejunum
Ileum

10. Villi

11. Villus

12. Absorption in Villi

14. Absorption in the small intestine
Passive transport is the movement of materials across a cell membrane without the use of cell energy
Amino acid will enter the bloodstream through the walls of the small intestine in a process referred to as diffusion ( area of higher conc. To lower conc.)
Water will diffuse through the cell membrane in a process called osmosis (higher conc. Of water molecule- to lower conc.)

15. Absorption in the small intestine
Facilitated diffusion is an example of passive transport.
Facilitated diffusion is the diffusion of molecules across a cell membrane via a transport protein
Carbohydrates are broken down into disaccharide and monosaccharide and they diffuse through cell walls using special transport proteins

16. Absorption in the small intestine
Active transport is the transportation of materials through a cell membrane using energy from the cell (it happens from a area of low conc to high)

17. Large Intestine & Appendix
Approximately 1.5 m long, about 7.6 cm wide
Cecum is where the small and large intestine meet (blind pouch)
The appendix is a small finger like projection from the cecum (no function)
The colon is longest part of the large intesitne. Comprised of the ascending, transverse, descending and sigmoid colon
Absorbs water, vitamins and minerals
rectum: last 20 cm of large intestine.Stores waste (feces)
Eliminates feces through the anus

19. Appendix/caecum In humans the appendix has no known function.
In herbivores such as rabbits the appendix or caecum is used to digest cellulose.

20. Conclusion: 5 steps of the process..
Ingestion - taking in food.
Digestion – breaking down food.
Absorption – digested food goes into the blood.
Assimilation – digested food is used by the body.
Egestion:- Elimination, waste is removed from the body.

21. Summary of Digestive Enzymes
FOOD TYPE
ENZYME
SOURCE
PRODUCTS
CARBOHYDRATES
Salivary amylase
Pancreatic amylase
Maltase
Salivary glands
Pancreas
Small intestine
Maltose
Glucose
PROTEINS
Pepsin
Trypin
Peptidases
Stomach mucosa
Intestinal mucosa
Peptides
Amino acids
FATS
Lipase
Fatty acids and glycerol

22. Enzymes by source SOURCE ENZYME FOOD PRODUCT MOUTH (salivary glands)
Salivary amylase
Polysaccharides
Maltose
STOMACH
Pepsin
Proteins
Peptides
PANCREAS
Pancreatic amylase
Trypsin
Lipase
Fats
Fatty acids
and glycerol
SMALL INTESTINE
Maltase
Peptidases
Glucose
Amino acids

23. Resources http://www.innerbody.com/htm/body.html

24. Salivary gland Teeth Tongue Epiglottis Esophagus Liver Stomach
Gall Bladder
Duodenum
Bile duct
Pancreas
Colon
(Large Intestine)
Small Intestine
Appendix
Rectum
(Anus)

25. Pancreas
Gall Bladder
Pancreatic Duct
Bile duct
Duodenum

26. Cells produce enzymes and
Epithelial Lining
Cells produce enzymes and
absorb digested food
Artery
Lymph vessel
Vein

27. Digestion of Starch
“Carbohydrates are digested in the mouth, stomach and small intestine. The saliva in your mouth contains amylase. If you chew a piece of bread for long enough, the starch it contains is digested to sugar, and it begins to taste sweet.” BBC. Bitesize biology,

28. Digestion of Proteins
“Proteins are digested in the stomach and small intestine. Digestion of proteins in the stomach is helped by stomach acid, which is strong hydrochloric acid. This also kills harmful micro-organisms that may be in the food.” BBC; bitesize biology.

29. Digestion of Fats (lipids)
“Digestion of fat in the small intestine is helped by bile, made in the liver. Bile breaks the fat into small droplets that are easier for the lipase enzymes to work on.” BBC; bitesize Biology