Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

The digestive system.


Published on

The nutrition function: the digestive system.

Published in: Education
  • Be the first to comment

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.
  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:  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