1. Digestive System

2. Digestive System Rap

3. Job of Digestive System Break down food (macromolecules) into nutrients & energy

4. Review: Macromolecules What macromolecules do we eat? Proteins: Meat, Nuts Lipids: Oils, Fats Carbohydrates: Breads, Sugars

5. Review: Food Energy Which macromolecule is our main energy source? Carbohydrates

6. Which macromolecule stores the most energy? Lipids Review: Food Energy (cont.)

7. The Food Pyramid

8. Nutrition Nutrients: Anything that promotes growth  Vitamins (Vitamin C) Minerals (Iron) Macromolecules

9. Two Types of Digestion Mechanical – physically breaking food into smaller pieces (mouth) Chemical – food molecules are broken down by acids and enzymes (stomach, small intestines)

10. Digestive System

11. Tracking a Piece of Food 1. Mouth 2. Esophagus 3. Stomach 4. Small Intestine 5. Large Intestine 6. Rectum 7. Anus

12. Swallowing Peristalsis: wavelike movement of muscles  pushes food through digestive tract

13. My food went down the “wrong pipe!” 2 tubes in throat: trachea & esophagus esophagus connects mouth to stomach How does food know which tube to go down? epiglottis

14. 3 Jobs of Stomach 1. Store food & liquid 2. Mix food & digestive juices (HCl) 3. Empty into small intestine

15. Digestive Juices Assist in breaking down of food Ex. Enzymes Acid Reflux

16. Small Intestine Absorbs greatest amount of nutrients Covered with tiny finger-like projections – villi ~20 ft long!

17. Villi Increase surface area for better absorption (like a towel)

18. Large Intestine Prepares waste for removal by absorbing water ~5 ft long!

19. Digestion: ‘Helper’ Organs Salivary Glands: produce saliva – starts breaking down carbohydrates Pancreas: produces enzymes & regulates glucose levels

20. Liver: Produces bile Filters blood Digestion: ‘Helper’ Organs (cont.)

21. Gall Bladder: stores bile Helps digest fatty foods Digestion: ‘Helper’ Organs (cont.)