digestive system

• describe role of the digestive system

  digest and absorb food
• give pathway of digested food

  1. mouth
  2. gullet / oesophagus
  3. stomach
  4. small intestine
  5. large intestine
  6. rectum
  7. anus
• describe digestion of food in mouth

  mechanical digestion of churning and release of amylase
• describe digestion of food in stomach

  pummels food, produces protease (pepsin) and produces hydrochloric acid
• describe role of hydrochloric acid in stomach

  kills microorganisms and provides optimal pH for protease pepsin enzyme action
• describe digestion in small intestine

  produce digestive enzymes, contains bile and absorbs food into bloodstream
• describe role of bile

  neutralise hydrochloric acid from stomach and emulsifies fat
• give areas of production of bile

  liver
• give areas of use of bile

  small intestine
• describe role of digestive enzymes

  convert food into small food molecules to be absorbed into blood
• give digestive enzymes

  carbohydrase, protease and lipase
• describe role of carbohydrase

  break down starch into simple sugars
• give areas of production of carbohydrase

  salivary glands, small intestine and pancreas
• give areas of use of carbohydrase

  mouth and small intestine
• describe role of protease

  breaks down proteins into amino acids
• give areas of production of protease

  stomach, small intestine and pancreas
• give areas of use of protease

  stomach and small intestine
• describe role of lipase

  break down lipids into glycerol and fatty acids
• give areas of production of lipase

  small intestine and pancreas
• give areas of use of lipase

  small instestine
• give uses of products of digestion

  build new carbohydrates, proteins and lipids and glucose used in respiration
• describe test for sugar

  benedicts - blue to brick red/yellow/green
• describe test for starch

  iodine - brown/orange to blue black/black
• describe test for protein

  biuret reagent - blue to purple
• describe test for lipids

  sudan III - colourless to red line on top layer of solution