Digestive System

• Digestive system

  Breaks down food into tiny particles which are absorbed into the blood. These particles provide energy for the body to grow, repair itself and remain healthy. Food that cannot be broken down is released from the body as faeces (poo).
• Digestive process


  Food passes through most parts of the digestive system in a journey from the mouth to the anus
• Parts of the digestive system

  • Mouth
  • Oesophagus
  • Liver
  • Stomach
  • Pancreas
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Mouth

  Digestion of food starts here. Teeth break down the food and mix it with enzymes in saliva.
• Oesophagus


  A thin tube that connects the mouth to the stomach.
• Liver

  Releases a chemical called bile into the intestines. Bile breaks down lipids in the food.
• Stomach


  A muscular bag which mixes food and drink with acid.
• Pancreas

  Releases enzymes into the intestines which break down carbohydrates, protein and lipids in food.
• Small intestine

  Here, carbohydrates, proteins and lipids digest. The nutrients produced are then absorbed into the blood.
• Large intestine


  Food which cannot be broken down - mainly fibre - passes into the large intestine. Water is absorbed into the blood.
• Rectum

  Any undigested food passes into the rectum where it is stored as faeces.
• Anus


  The opening at the very end of the digestive system through which faeces leaves the body.
• Your mouth produces about 1.5 litres of saliva each day.
• Mechanical and chemical digestion

  Teeth break down food mechanically. Enzymes digest food chemically.
• Bile

  Produced by the liver and stored in the gall bladder. Released into the small intestine to break down large molecules of lipids into smaller ones.
• Emulsification

  The breakdown of large drops of lipid into smaller droplets. This increases the surface area for enzymes to act upon.
• Peristalsis


  The rhythmical contraction of muscles lining the oesophagus, and small and large intestines to squeeze food through them.
• Villi

  Specialised structures in the small intestine with a tiny hair-like structure poking into the small intestine to absorb digested food.
• If we stretched out all the folds in the small intestine this would be the area of a tennis court.