The digestive system

• Tissue


  A group of cells with a similar structure and function
• Organ


  A group of tissues working together for a specific function
• Organ system


  Organs grouped together to form organisms
• Main nutrients in food

  • Carbohydrates
  • Protein
  • Lipids (fats)
• Digestion


  1. Large food molecules broken down into small molecules by enzymes

  2. Small molecules absorbed into bloodstream
• Main organs of the digestive system

  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Liver
  • Pancreas
• Mouth


  • Food chewed, enzymes in saliva begin to digest starch
• Esophagus


  • Food passes from mouth to stomach
• Stomach


  • Enzymes begin digestion of proteins, contains hydrochloric acid, churning action turns food into fluid
• Small intestine


  • Chemicals from liver and pancreas continue digestion of starch, protein and lipids
  • Small food molecules absorbed into bloodstream
• Large intestine


  • Water absorbed into bloodstream, feces released from body
• Products of digestion used by body to build new carbohydrates, lipids and proteins
• Some glucose produced is used in respiration