2. Digestion: What your body does with food Unit 1 Topic 6

3. CATALYST: Can you match a letter to the following body parts: Small intestine Esophagus Stomach Large intestine Liver Pancreas

4. Stages of food processing Ingestion Digestion –Mechanical –Chemical Absorption Elimination

5. Mouth (oral cavity) Functions –mechanical digestion –chemical digestion –Saliva also contains… mucus buffers anti-bacterial chemicals

6. Swallowing Epiglottis Peristalsis

7. Stomach Functions –disinfect food –food storage –digests protein –mechanical digestion But the stomach cells contain protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining

8. Small intestine Functions –Chemical digestion –Absorption This is where all the work is done!

9. Absorption in Small Intestines Absorption through villi & microvilli SMALL INTESTINES 6 meters long, but can stretch to cover a tennis court

10. Accessory organ: Pancreas Produces digestive enzymes that function in the small intestine for chemical digestion Also produces buffers

11. Accessory organs: Liver & Gall Bladder Liver produces bile Gallbladder stores bile

12. Function –re-absorbs water –compact waste for elimination Large intestines (colon)

13. You’ve got company! Living in the large intestine is a community of helpful bacteria –Escherichia coli: E. coli digest cellulose produce vitamins –vitamin K & B vitamins BUT generate gases –by-product of bacterial metabolism –methane, hydrogen sulfide