sr

• Mouth


  The beginning of the digestive system, where digestion starts
• Digestion in the mouth


  1. Smell of food triggers salivary glands to secrete saliva

  2. Saliva contains carbohydrase which chemically breaks down carbohydrates

  3. Mechanical digestion through chewing breaks down food into smaller pieces
• Oesophagus


  • Carries food to the stomach
  • Muscular tube
  • Food is pushed through by peristalsis
• Stomach


  • Produces protease enzymes which digest protein
  • Muscular walls contract to churn the food, breaking it into smaller pieces and increasing its surface area
  • Contains hydrochloric acid which kills ingested bacteria
• Liver


  • Makes bile
  • Bile is alkaline to neutralise hydrochloric acid from the stomach
  • Bile emulsifies fat to form small droplets which increases the surface area
• Gallbladder


  Stores excess bile before it is released into the small intestine
• Pancreas


  • Produces digestive enzymes (carbohydrase, lipase, protease) which are secreted into the small intestine
  • Enzymes break down proteins, fats, and carbohydrates
• Digestion in the small intestine

  1. Produces protease, amylase and lipase that continue digestion

  2. Soluble products of digestion are absorbed into the blood through the walls which are covered in projections called villi
• Large intestine


  • As stool passes through, water is absorbed into the blood
  • Stool is mostly fibres and bacteria
• Rectum


  • Receives stool from the large intestine
  • Lets the person know there is a stool to be evacuated
  • Holds the stool until evacuation happens
• Anus


  The last part of the digestive tract