3.1

• function of digestive system - break down food into smaller pieces so that they can be used by the body
• mechanical digestion - physical breakdown of food into smaller peices
• mechanical digestion

  1. teeth
  2. tongue
  3. stomach churning
• chemical digestion

  1. salivary glands
  2. gastric juices
  3. pancreas sending enzymes to small intestine
  4. liver and gallbladder sending bile
• chemical digestion - involves breakdown of large particles into smaller particles
• mouth - food enters here

  • Teeth grind food
  • salivary glands moisten food and start to break it down
• saliva - contains an enzyme salivary amylase
• epiglottis - a flap of skin that moves across windpipe when food enters esophagus

  • protects you from choking
• peristalsis - when the muscles that line the esophagus contract

  • pushes food down into stomach
• stomach - muscular wall churns food

  • creates gastric juices that digest proteins into smaller particles
  • mucus in stomach prevents stomach from digesting itself
• small intestine - absorbs food particles

  • pancreas sends digestive enzymes that complete the breakdown of starches and proteins
  • the liver produces bile which is stored in the gallbladder - sends bile
• villi - small finger like projections that increase the surface area of the intestine to aid in absorbing nutrients

  • covered with epithelial tissue
  • capillaries are just below the the tissue to disperse nutrients into the blood stream
• microvilli - finger like projections coming off of the villi that further increase the surface area for absorption of nutrients
• large intestine - digestion is complete

  • absorbs water, minerals and vitamins
  • anything not collected forms feces in the rectum