2. Do NowDo Now  List the path of this morning’s breakfast through the Digestive Tract, from start to finish

3. Do NowDo Now  Mouth  Pharynx  Esophagus  Stomach  Small Intestines  Large Intestines  Rectum

4. Gallbladder  Located right below liver  Stores bile  Helps break down large fat molecules into smaller particles  Fat gets absorbed, the then the bile is also reabsorbed back into the liver

5. Large IntestinesLarge Intestines  Last major part of the digestive system  Function is to remove water from indigestible food, and then pass waste material from the body  Takes approx. 16 hours to finish digestion

6. Liver  Important in metabolism, glycogen storage and detoxification  Many vital functions  Secretes bile  Cannot live without a liver

7. Small IntestinesSmall Intestines  Digestion using enzymes  Main site of absorption of nutrients  Includes  Duodenum  Jejunum  Ileum  Don’t get punched in the jejunum…  https://www.youtube.com/watch?v=oHulRDk__ko https://www.youtube.com/watch?v=oHulRDk__ko

8. Review  STOMACH  The diameter and volume of the stomach varies depending on the amount of food it contains  Can hold up to 1 gallon of food  When it is empty, it collapses inward and folds into “rugae”  Main functions  “Storage tank”  Food break down  Minimal absorption

9. Stomach  Site of breakdown of proteins  Contains deep gastric pits which house protein- digesting enzymes  What is an enzyme?  Cells produce Hydrochloric Acid creating a highly acidic nature in the stomach  Stomach maintains a pH of approx. 2.0  Very Acidic? Mildly Acidic? Mildly Basic? Very Basic?

10. pH ScalepH Scale

11. Stomach  If the stomach is so acidic, why does it not eat away at itself?  The Answer: Mucous  Ulcers are the result of gastric juice penetrating the lining of the stomach  Caused by bacteria becoming present on the stomach lining and prevents the secretion of mucous

12. Ulcers

13. Duodenum  First part of the small intestines  Chyme enters duodenum by spurts from the stomach  Chyme?  Proteins and carbohydrates are now partially digested  Fats not yet started to become digested

14. Pancreas  Releases pancreatic juice into the small intestines  Neutralizes the acidic material from the stomach

15. Small IntestinesSmall Intestines  Approximately 3 meters long  Numerous projections called villi that function to increase surface area  Total surface area of 500-600 square meters  Why is increased surface area important?

16. Large IntestinesLarge Intestines  Also called the colon  Colon cancer?  Receives approximately 10 liters of water per day  1.5 L from food  8.5 L is from secretions  Last major part of the digestive system  Function is to remove water from indigestible food, and then pass waste material from the body  Takes approx. 16 hours to finish digestion

17. Large IntestinesLarge Intestines  Also absorbs sodium and other ions  If water is not absorbed, diarrhea can result  Causes dehydration and ion loss

18. Polyps  Small growths in the lining of the colon (large intestines)  Cancerous (malignant) or benign  Benign?  Low-fat, high-fiber diets are recommened to protect against colon cancer

19. Homework  Read 3/31 p. 470-474  Split page notes – ATLEAST 1 page