LESSON #1 IN SCIENCE (DIGESTIVE SYSTEM)

• Digestive system


  Used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body
• Digestive processes


  1. Ingestion

  2. Digestion

  3. Absorption

  4. Assimilation

  5. Egestion
• Ingestion


  The process where food is taken in through the mouth and broken down by teeth and saliva
• Digestion


  Breaking down of food into small pieces
• Mechanical digestion


  • Physical breakdown of large pieces of food into smaller pieces
• Chemical digestion


  • Carried out by the enzymes that speed up the chemical reaction
• Absorption


  The process by which food molecules move into the blood stream to be carried to the cells of the body
• Assimilation


  Incorporation of food molecules into the cells of the body to be used as energy, structural materials or storage products
• Egestion


  The process of eliminating undigested food from the body
• Plants, animals, and microorganisms are all forms of life
• Parts of a plant


  • Leaf
  • Stem
  • Root
• The Integumentary System includes hair, skin, and nails and its function is covering and protection
• The Digestive System's function is to break down food into small pieces that can be absorbed by the body cells
• Main organs of the Digestive System

  • Mouth
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine (colon)
• Accessory organs of the Digestive System

  • Pancreas
  • Gall Bladder
  • Liver
• Digestion


  The breakdown of food
• Mouth


  • Where digestion begins (mechanical)
  • Contains teeth
  • Contains tongue with taste buds (taste)
  • Contains salivary glands that produce saliva (1.5L) which softens, melts, and moistens food
  • Contains enzymes like ptyalin, amylase, and maltase that speed up digestion
• Esophagus


  • Muscular tube that connects the mouth to the stomach
  • Contains peristalsis (wave-like muscular movement)
• Stomach


  • J-shaped muscular organ that temporarily stores food for 3-4 hours
• Hydrochloric acid (HCI)


  Gastric acid that kills bacteria
• Lipase/Protease enzymes


  • Breakdown protein
• Small Intestine


  Where final digestion takes place
• Absorption of food nutrients

  • To the blood cells because of villi
• Accessory Organs


  • Liver
  • Gall Bladder
  • Pancreas
• Liver


  Secretes bile
• Gall Bladder


  Stores bile
• Pancreas


  Makes insulin for sugar
• Large Intestine (colon)


  Undigested food eliminates
• Rectum


  Stores feces
• Anus


  Opening where feces eliminates in process called defecation