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The digestive system.

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The nutrition function: the digestive system.

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The digestive system.

  1. 1. THE NUTRITION FUNCTION I. The digestive system.
  2. 2. The nutrition function.  Taking in of nutrients (found in food) which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them.  In multicellular organisms, several systems take part in this function.  Digestive system.  Respiratory system.  Circulatory system.  Excretory system. Intimately interlinked. Endocrine and nervous system also participate.
  3. 3. Digestive System Processes.  Ingestion : Intake of food into the body through mouth.  Digestion: The process of break-down of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes.  Absorption : The process of passing digested food molecules across the wall of the intestine into the blood or lymph.  Assimilation : The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.  Egestion : Passing out of undigested food, in the form of faeces, through the anus.
  4. 4. Digestion Mechanical Chew Tear Grind Mash Mix Chemical Carbohydrates Lipids Protein s (physical) Enzymatic reactions to improve digestion of
  5. 5. Digestive System Organization • Gastrointestinal tract. • Accessory glands.
  6. 6. Digestive System Organization • Gastrointestinal tract. – Direct link/path between organs, 8m. – Shape varies. – Secrete mucus (ˈmjuːkəs) or digestive juices. – Structures • Mouth • Pharynx • Esophagus • Stomach • Small intestine • Large Intestine • Rectum
  7. 7. Digestive System Organization.  Gastrointestinal tract.  Accessory organs.  Not part of the path of food, but play a critical role.  Include:  Salivary glands,  liver, gall bladder, and  pancreas
  8. 8. Mouth  Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing the bolus from  CHEWING: Teeth mechanically break down food into small pieces.  SALIVATION: Tongue mixes food with saliva (contains amylase (ˈæmɪleɪz), which helps break down starch).  SWALLOWING: the tongue push the bolus towards the pharynx.
  9. 9.  Saliva (səˈlaɪvə) is a watery liquid released by salivary glands.  Starts digestion of starch molecules: AMYLASE (ˈæmɪˌleɪz).  Destroys some bacteria: LYSOZYME (ˈlaɪsəˌzaɪm).  Eases the bolus into
  10. 10. PHARYNX  It is a common passageway for air and food. It participates in swallowing (ˈpælɪt) (ɛpɪˈɡlɒtɪs) (ɪˈsɑfəgəs)
  11. 11. Esophagus  Approximately 20- 25cm long  Functions include: 1.Secretes mucus 2.Moves food from the throat to the stomach using muscle movement called peristalsis (pɛrɪˈstælsɪs)  If acid from the stomach gets in here that’s heartburn (cardia at the entering of the stomach stops
  12. 12. Stomach  J-shaped muscular bag that stores the food you eat, and digests it.  Mixes food with digestive juices that contain enzymes to break down proteins (pepsine) and lipids.  HYDROCHLORIC ACID in the stomach kills bacteria, and supports enzyme’s work.  It absorbs water, alcohol and some drugs.  Food in the stomach is called chyme (kaɪm), once it has mixed with gastric juices. The stomach takes around 4 hours to do it’s job on the food, depending on what kinds of food are digested.
  13. 13. cardia paɪˈlɔːrəs ˈkɑːdɪə djuːəʊˈdiːnəm
  14. 14. Small Intestine  Small intestines are roughly 7 meters long, finishing in the ileocecal valve.  Intestine walls have finger-like projections called villi, to increase surface area.  The villi are covered in microvilli which further increases surface
  15. 15. Small Intestine  Nutrients from the food pass into the bloodstream through the small intestine walls.  Establishes an optimal pH for enzymes.  Secretes digestive enzymes.  Absorbs:  80% ingested water.  Vitamins.  Minerals.  Carbohydrates.  Proteins.  Lipids.
  16. 16.  When the chyme mixes with intestinal juices, and secretions from liver and pancreas, it transforms into chyle (kaɪl).  The first part of intestine (duodenum) receives following secretions.  Pancreatic juice from pancreas.  Bile juice from liver.
  17. 17. Liver  Directly affects digestion by producing bile  Bile helps digest fat. • Filters out toxins and waste including drugs and alcohol.  Bile does not contains any enzymes.  Bile contains bile salts which acts on fats.  Bile salts break fats up into smaller fat droplets which can be more easily digested by lipase.23
  18. 18. Gallbladder  Stores bile from the liver, releases it into the small intestine.  Bile is realeased through the ampulla of Vader.  Fatty diets can cause gallstones.
  19. 19. Pancreas  Produces digestive enzymes to digest fats, carbohydrates and proteins.  Regulates blood sugar by producing insulin, a hormone.  Pancreatic juice also neutralizes the acid liquid from the stomach.
  20. 20.  After digestion, simpler molecules are obtained:  Monosaccharides.  Glycerol and fatty acids.  Amino acids.  Those nutrients are absorbed through the small intestine inner layer. Capillaries collect them.
  21. 21. Large Intestine  About 1’5 m long.  Accepts what small intestines don’t absorb.  Functions  Bacterial digestion  Ferment carbohydrates  Protein breakdown Absorbs more water.  Concentrates wastes.
  22. 22. Large Intestine  Portions of the large intestine,  ascending,  transverse,  descending,  sigmoid, and  Rectum. The rectum is the short term storage which holds feces before it is expelled).
  23. 23. https://www.youtube.com/watch?v=8YXKklSxW30
  24. 24. Write the name of each colored organ:  Green:  Red:  Pink:  Brown:  Purple:  Green:  Yellow:
  25. 25. How’d you do?  Green: Esophagus  Red: Stomach  Pink: Small Intestine  Brown: Large Intestine  Purple: Liver  Green: Gall Bladder  Yellow: Pancreas
  26. 26. References and Links  Inner body: http://www.innerbody.com/  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

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