1. Digestive system 1.Why do we need to eat? A: To obtain energy 2.What gives us energy? A: The nutrients in food and drinks 3.How do we get those nutrients from food? A: The body evolves the digestive system 4. So what do you think is the function of the digestive system?

2. Recall The adventure of eaten food

3. Digestive system - Pica http://edition.cnn.com/2004/ HEALTH/02/18/coin.eater.ap /index.html

4. Human digestive system Mechanical breakdown of food: incisors: slicing & gripping canines: ripping & tearing premolars: bitting & tearing molars: grinding Chemical breakdown of food: saliva

5. Human digestive system Food  bolus Peristalsis pushes bolus towards the stomach via muscle contraction

6. Human digestive system Secretes HCl and pepsin to chemically digest the food Digestion takes place in the bowel, bottom of the stomach

7. Human digestive system

9. Liver secretes bile bile digest fat

10. Human digestive system Pancreas secretes proteins to digest protein, and neutralize stomach acid

11. Digestive system