The Digestion System

1. The Digestion System Ch 38-2 Guide Mechanical & Chemical Breakdown Of Food for energy

2. I 1) Mouth: Mechanically breaks up food Chemically digests • Carbohydrates • Basic pH • Enzyme amylase from salivary glands Wets & forms “bolus”

3. Esophagus • Bolus movement to stomach by peristalsis • (see video)

4. 2. Stomach Mechanically churns Stores food Chemically digests • Acid pH • Proteins Enzyme Pepsin Mucus Lining prevents digestion of itself !

5. 3. Small Intestine Absorption of food Digestion of • Lipids (fats) • Carbohydrates Uses Lipase & Amylase from the pancreas

6. 4. Large Intestine • Absorbs water & vitamins • No Digestion • Eliminates wastes

7. Barium Enema: window to the intestines:

8. 5. Salivary Glands: • Makes the salivary juices • Contains amylase enzymes • Basic pH • For the digestion of carbohydrates

9. 6 Liver:.Makes bile & Stores sugar as glycogen No food passes through the liver No digestion takes place in the liver Gall Bladder stores bile

10. 7.Gall Bladder: Stores bile made by the liver • Bile emulsifies fats • Makes them water soluble • In small intestine No food passes through the gall bladder No digestion takes place in the gall bladder

11. Carter’s Little Liver Pills: cure=all • Liver also cleanses the blood • Carter’s pills claimed to cure constipation, headaches, skin problems???

12. 8.Pancreas makes digestive juices:Enzymes & Acids or bases No Digestion in the Pancreas ! No food passes through here

13. 9. Appendix: vestigial organ

14. Intracellular: Inside a cell Food vacuoles Small particles Examples: Amoeba, Paramecium Extracellular: In a sack or tube Larger food Then absorbed into a cell Humans Types of Digestion:

15. Proteins Carbo-hydrates Lipids Amino acids subunits Muscle,enzymes,Hb Last use for food Simple sugar (glucose) Quick energy food 1st used Fatty acids & glycerol Long term food, insulation,protection 2nd used for food Digestion Products:

16. Digestion: Is • Breaking down food • physically & chemically For • The purpose of distributing small water soluble particles to the cells for energy

17. Homeostasis • Maintaining balance • “homo”=same • “stasis”=state • By constant adjustments • For survival

18. pH= Proper acid or base levels • Basic = > 7 • Digestion of carbohydrates & lipids • Acidic= < 7 • Digestion of proteins in the stomach pH 2 7 8 1 0 12

19. Proteins Catalysts Speed reactions Work fast Denature at high temp Properties of Enzymes

20. Enzyme-Substrate complex Active site = where the substrate ( reaction molecule) connects to enzyme Active Site Substrate Enzyme

21. Lock & Key Model • One enzyme • for every substrate • unique fit Substrate Enzyme

22. Enzymes are pH specific • Different enzymes • Different body areas • Different optimum pH Stomach= acid pH Uses PEPSIN Mouth= basic pH Uses AMYLASE Blood Mouth Stomach

23. Bile: Made in Liver Stored in Gall Bladder • Emulsifies fats • Makes them water soluble • In small intestine

24. Villi: Small intestine absorb food Many “finger-like” villi maximize surface area

25. 8.Peristalsis: • Contractions of the Digestive system • Moves food down • Controlled by the autonomic nervous system

26. Control of Digestion by the Nervous System