Digestion Slides for class 11 and all classes of Sciences
- 2. Digestion • Phases Include 1. Ingestion 2. Movement 3. Mechanical and Chemical Digestion 4. Absorption 5. Elimination
- 3. Digestion • Types – Mechanical (physical) • Chew • Tear • Grind • Mash • Mix – Chemical • Enzymatic reactions to improve digestion of – Carbohydrates – Proteins – Lipids
- 4. Mouth • Teeth mechanically break down food into small pieces. Tongue mixes food with saliva (contains amylase, which helps break down starch). • Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it.
- 5. Esophagus • Approximately 10” long • Functions include: 1. Secrete mucus 2. Moves food from the throat to the stomach using muscle movement called peristalsis • If acid from the stomach gets in here that’s heartburn.
- 6. Stomach • J-shaped muscular bag that stores the food you eat, breaks it down into tiny pieces. • Mixes food with digestive juices that contain enzymes to break down proteins and lipids. • Acid in the stomach kills bacteria. • Food found in the stomach is called chyme. 6
- 7. Small Intestine • Small intestines are roughly 7 meters long • Lining of intestine walls has finger-like projections called villi, to increase surface area. • The villi are covered in microvilli which further increases surface area for absorption. • Bile aids in the chemical digestion of lipids • Enzymes continue to digest carbohydrates, lipids and proteins. 7
- 8. 10/13/2014 8
- 9. Small Intestine • Nutrients from the food pass into the bloodstream through the small intestine walls. • Absorbs: – 80% ingested water – Vitamins – Minerals – Carbohydrates – Proteins – Lipids • Secretes digestive enzymes 9
- 10. Large Intestine • About 5 feet long • Continues to absorb water • Rectum (short term storage which holds feces before it is expelled).
- 11. Large Intestine – Absorbs more water – Concentrate wastes
- 12. Accessory Organs • Not part of the path of food, but play a critical role. • Include: Liver, gall bladder, and pancreas
- 13. Liver • Directly affects digestion by producing bile – Bile helps digest fat • filters out toxins and waste including drugs and alcohol 13
- 14. Gall Bladder • Stores bile from the liver, releases it into the small intestine. • Fatty diets can cause gallstones
- 15. Pancreas • Produces digestive enzymes to digest fats, carbohydrates and proteins • Regulates blood sugar by producing insulin
- 16. How’d you do? • Green: Esophagus • Red: Stomach • Pink: Small Intestine • Brown: Large Intestine • Purple: Liver • Green: Gall Bladder • Yellow: Pancreas
- 17. References and Links • Your Digestive System and How It Works – Digestive system diagram comes from this site • The Real Deal on the Digestive System • Pancreas: Introduction and Index • Your Gross and Cool Body - Digestive System