Digestion

• Digestive system


  The job is to break down large food molecules, called digestion
• Digestion


  1. Physical

  2. Chemical
• Physical digestion


  • Occurs in the mouth where the teeth break up the food into smaller pieces
  • Food is broken down further by the stomach's muscular walls
• Chemical digestion


  • Caused by digestive enzymes that are released at various points along the digestive system
  • Substances our body needs cannot be absorbed into our blood until they have been broken down further and converted into small soluble chemicals
• Absorption


  Once the food molecules have been digested, they are small enough to diffuse into the bloodstream or lymph vessels
• Peristalsis


  The movement of food through the digestive system by the contractions of two sets of muscles in the walls of the gut
• Digestion in the stomach

  1. Carbohydrate is turned into glucose

  2. Protein is turned into amino acids

  3. Fats and oils are turned into fatty acids and glycerol

  4. Vitamins and minerals do not have to be digested
• Digestive process


  1. Chemical digestion starts in the mouth

  2. Food moves to the stomach

  3. Small intestine receives the food and produces protease and lipase, food is absorbed into blood through villi

  4. Large intestine is where indigestible food is passed to and excess water is absorbed before it is excreted
• Gall bladder


  • Stores bile after its been made by the liver
• Pancreas


  • Produces enzymes: carbohydrase, lipase, protease
• Villi


  Small projections covering the inside walls of the small intestine, food products pass into the blood stream through the villi