The Digestive system. Parts and functions
- 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. Digestive System Organization • Gastrointestinal (Gl) tract Gastrointestinal (Gl) tract – Tube within a tube Tube within a tube – Direct Direct link/path link/path between organs between organs – Structures Structures • Mouth Mouth • Pharynx Pharynx • Esophagus Esophagus • Stomach Stomach • Small intestine Small intestine • Large Intestine Large Intestine • Rectum Rectum 4
- 5. 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. It is located in the Pharynx.
- 6. Esophagus • Approximately 20 cm 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. Mouth, Pharynx and Esophagus Video Video
- 7. Stomach 7 • 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 Proteins and Lipids. • Acid (HCl) in the stomach Kills Bacteria. • Food found in the stomach is called Chyme.
- 8. 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. 8 Crash Course Review
- 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 1.5 meters long • Accepts what small intestines don’t absorb • Rectum (short term storage which holds feces before it is expelled).
- 11. Large Intestine • Functions – Bacterial digestion • Ferment carbohydrates – Absorbs more water – Concentrate wastes
- 12. Accessory Organs The Glands • 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 and poisons. 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 Web Page Web Page Reinforcement Video
- 17. On a sheet of paper, write the name of each colored organ: • Green: • Red: • Pink: • Brown: • Purple: • Green: • Yellow:
- 18. How’d you do? • Green: Esophagus • Red: Stomach • Pink: Small Intestine • Brown: Large Intestine • Purple: Liver • Green: Gall Bladder • Yellow: Pancreas Great Job!
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- 21. 08/15/24 21
Editor's Notes
- #6: A good way to describe peristalsis is an ocean wave moving through the muscle. These diagrams don’t separate the esophagus from the mouth functions, you might want to talk about what happens in the mouth too.
- #7: The stomach takes around 4 hours to do it’s job on the food, depending on what kinds of food are digested.
- #10: Depending on the maturity of the group, you can talk about the feces leaving via the anus. Mention the appendix at the bottom of the ascending colon and that it might have been used long ago but is not today Mention the portions of the large intestine, ascending, transverse, descending, sigmoid, and rectum (last one if the audience is mature enough)
- #13: Livers can regenerate missing pieces if necessary. Is one of the largest organs in the body.
- #14: Explain to students that removing the stones typically means removing the gallbladder, but that the body eventually adjusts to not having the bile stored.
- #15: Explain the difference between the two types of diabetes. In type 1, the pancreas fails to produce enough insulin. In type 2, the body stops responding properly to the insulin it creates.