1. The Digestive System A Closer Look

2. QOTD – Label Me!

3. Answers Tongue Esophagus Stomach Duodenum Pancreas ileum
Large Intestine
Rectum

4. Purpose:
To enable the absorption of the nutrients needed for growth, maintenance and repair

5. Components of Digestion
Ingestion
= the taking in of nutrients
= enters by mouth
Digestion
= the breakdown of complex organic molecules into smaller components by physical & chemical means
Mechanical – done by teeth, and stomach
Chemical – done by the mouth, stomach,
liver, gallbladder, pancreas, small & large intestine.

6. Break It Down Now! Enzymes
Carbohydrases break down ________
Peptidases break down… ________
Lipases break down… ________
SEE HANDOUTS!

7. Absorption The taking up of digested molecules into cells
Done by stomach, small intestine (villi), large intestine
small intestine (villi)

8. Absorption
The Small Intestine is designed to have a large surface area.
The inner membrane is folded like a fan
The entire surface is covered with villi (villus)
Each villus is covered with microvilli
Absorption involves diffusion and active transport

9. Anatomy of a Villus Microvilli Proteins Capillary Lacteal
BEFORE DIGESTION…
TOO BIG!!
Starches
AFTER DIGESTION…
SMALL ENOUGH!!
Water
Minerals TO BLOOD
Water soluble vitamins (B, C)
Glucose
Amino Acids
Lipids
Glycerol TO LYMPH
Fatty Acids
Fat soluble vitamins (A, D, E, K)

10. Elimination The removal of waste from the body
Done by large intestine, rectum and anus

11. Control Mechanisms Regulation through feedback
Done by hormones (chemical messengers)
Thermostat Example:
-Too hot, shuts down
-Too cold, starts furnace

12. Digestion of Fats
When fats enter the duodenum, the hormone CCK (Cholecystokinia) is released which causes the gall bladder to release bile.
Fats are emulsified

13. Acidic Chyme
When acidic chyme enters the small intestine, the hormone secretin is released which causes the pancreas to release bicarbonate ions.
The acid is then neutralized!

14. Blood Glucose Levels
When glucose enters the blood stream, the pancreas releases Insulin.
Insulin stimulates the storage of glucose (as Glycogen, in the liver)
When blood glucose levels drop too low, the pancreas releases Glucagon.
Glucagon stimulates the release of glucose (from Liver) into the bloodstream

15. Blood Sugar Levels
Check out Page 270!

16. Digestive System Problems
1. Ulcer
A sore wall of the stomach (peptic) or duodenum (duodenal)
HCl creates a hole in the mucous lining…acid irritates muscles
Caused by bacteria that reduce amount of mucous.
Treated with antibiotics

17. Digestive System Problems
2. Cirrhosis of the Liver.
Scar tissue in liver.
Caused by excessive alcohol consumption and/or hepatitis virus.
Results in jaundice (yellow skin), nausea, pain, fluid in abdomen
Treatment…stop drinking!, vitamins, transplant.
Read Page 273!

18. Digestive System Problems
3. Inflammatory Bowel Disease
Crohn’s Disease and Ulcerative colitis
Inflammation of the lining of small or large intestine.
Treatment: Drugs, supplements or…
Resection and Colostomy
A stoma is created, and a pouch collects the waste.

19. Digestive System Problems
4. Acid Reflux
Stomach acid burns the tissue of the esophagus
Caused by a weak cardiac sphincter

20. Digestive System Problems
5. Constipation
Too much water is removed from feces
Usually because waste is moving too slowly…bunged up!
Treatment: Eat fibre! (cellulose), laxatives, suppositories.

21. A CURE FOR CONSTIPATION?