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LG: How do we digest food?

LG: How do we digest food?. DO NOW (11/18) What are some functions of the digestive system? List some digestive organs. Overview of the D.S. http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter26/animation__organs_of_digestion.html

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LG: How do we digest food?

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  1. LG: How do we digest food? DO NOW (11/18) What are some functions of the digestive system? List some digestive organs.

  2. Overview of the D.S. • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter26/animation__organs_of_digestion.html • http://science.nationalgeographic.com/science/health-and-human-body/human-body/digestive-system-article/ • http://www.youtube.com/watch?v=SyVcyT-fOao

  3. food O2 ATP What do animals need to live? • Animals make energy using: • Food (glucose) • Oxygen • Cellular Respiration mitochondria

  4. How do animals get their food? filter feeding living in your food fluid feeding bulk feeding

  5. Different diets; different lives • All animals eat other organisms • Herbivores • eat mainly plants • cows, rabbits Carnivores • eat other animals • sharks, hawks Omnivores • eat animals & plants • bears, raccoons, humans

  6. Getting & Using Food • Ingest • taking in food • Digest • mechanical digestion • breaking up food into smaller pieces • chemical digestion • breaking down food into molecules small enough to be absorbed into cells using enzymes • Absorb • absorb nutrients across cell membranes • diffusion • active transport • Egestion • undigested material passes out of body intracellulardigestion extracellulardigestion

  7. Digestive systems Everybody’s got one!

  8. Human digestive system

  9. Mouth • Functions • mechanical digestion • teeth • break up food • chemical digestion (saliva) • amylase enzyme • digests starch • mucus • protects soft lining of digestive system • lubricates food for easier swallowing • buffers • neutralizes acid to prevent tooth decay • anti-bacterial chemicals • kill bacteria that enter mouth with food All thatin spit!

  10. Swallowing (& not choking) • Epiglottis • flap of cartilage • closes trachea (windpipe) when swallowing • food travels down esophagus • Peristalsis • involuntary muscle contractions to move food along

  11. Normal Swallowing • http://www.linkstudio.info/images/portfolio/medani/Swallow.swf

  12. Esophagus Functions • Secrete (release) mucus • Transport food

  13. mouth break up food digest starch kill germs moisten food

  14. Stomach • Functions • disinfect food • hydrochloric acid = pH 2 • kills bacteria • food storage • digests protein • pepsin enzyme But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining

  15. stomach kills germs break up food digest proteins store food mouth break up food digest starch kill germs moisten food sphincter sphincter

  16. Malfunction: Ulcers • Used to think ulcers were caused by stress • Now know ulcers caused by bacterial infection of stomach • H. pylori bacteria • now cure with antibiotics

  17. Helicobacter pylori http://a-stomach-pain.com

  18. Revolutionizing healthcare 2005 Nobel prize in medicine J. Robin Warren Barry Marshall

  19. Small intestine • Functions • digestion • Digest: • carbohydrates • proteins • lipids (fats) • absorption • nutrients move into body cells by: • diffusion • active transport This iswhere all thework is done!

  20. Absorption in Small Intestines • Absorption through villi & microvilli • finger-like projections • increases surface area for absorption SMALL INTESTINES6 meters long,but can stretchto cover a tennis court

  21. small intestines breakdown food - proteins - starch - fats absorb nutrients through villi (diffusion) mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats pancreas produces enzymes to digest proteins & starch

  22. Pancreas: Digester and Regulator • Produces digestive enzymes • digest proteins • digest starch • digest lipids • Secretes insulin to lower blood sugar smallintestine pancreas

  23. pancreas produces enzymes to digest all foods -insulin lowers glucose level mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food

  24. Liver & Gall Bladder • Produces bile • breaks up fats • gallbladder only stores bile • that’s why you can have your gall bladder removed bile contains colors from old red blood cells collected in liver = iron in RBC rusts & makes feces brown

  25. Accessory Organs of Digestion Liver Gall Bladder Pancreas

  26. Accessory Organs of Digestion Liver Gall Bladder Pancreas Small Intestine Bile Bile

  27. Accessory Organs of Digestion Liver Gall Bladder Pancreas Small Intestine Bile Bile Amylase Lipase Trypsin

  28. Liver Cirrhosis: Too Many Poisons

  29. liver produces bile - stored in gall bladder break up fats mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food pancreas produces enzymes to digest proteins & starch

  30. Large intestines (colon) • Function • re-absorbs water • > 90% of water re-absorbed • not enough water re-absorbed • diarrhea • too much water re-absorbed • constipation • reabsorb by diffusion

  31. You’ve got company! • Living in the large intestine is a community of helpful bacteria • Escherichiacoli:E.coli • digest cellulose • digests fruits & vegetables • produce vitamins • vitamin K & B vitamins • BUT generate gases • by-product of bacterial metabolism • methane, hydrogen sulfide • STINKY! PEE-YOO!

  32. large intestines absorb water mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats small intestines breakdown food - proteins - starch - fats absorb nutrients through villi (diffusion) pancreas produces enzymes to digest proteins & carbs

  33. Appendix Vestigial organ

  34. mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats small intestines breakdown food - proteins - starch - fats absorb nutrients through villi (diffusion) pancreas produces enzymes to digest proteins & carbs large intestines absorb water appendix

  35. Parts of the digestive system • ___________________ • ___________________ • ___________________ • ___________________ • ___________________ • ____________________ • ____________________

  36. Rectum • Last section of large intestines • eliminate feces • what’s left over? • undigested materials • mainly cellulose from plants • called roughage or fiber • keeps everything moving & cleans out intestines • masses of bacteria So don’t forget to wash your hands!

  37. pancreas high liver low pancreas liver Homeostasis Balancing Blood Sugar levels insulin body cells takeup sugar from blood liver storessugar reducesappetite blood sugar level liver releasessugar triggershunger Feedback glucagon

  38. Summary

  39. Malfunctions of the Digestive System • 1. Ulcers • 2. Diarrhea • 3. Constipation • 4. Colon Cancer • 5. Pancreatic Cancer • 6. Liver Cirrhosis

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