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Understanding the Roles of Digestion

Understanding the Roles of Digestion

  Secondary | Health | Views: 738

  • The food we eat contains lots of nutrients which our body needs so we can stay fit and healthy. 
  • When we eat food, our digestive system helps to break food down into smaller pieces. 
  • Once the food is broken down into small enough pieces our body can then absorb all of the nutrients to keep us healthy.
  • This practical helps to show us how food is broken down and nutrients are absorbed as it moves through our body.

Note: This  is very messy, so be prepared to have a lot of cleaning up!

You Will Need:

  • A selection of your favourite foods such as beans and biscuits (the sloppier the better).
  • Two large bowls: one labelled Mouth and the other labelled Small Intestine.
  • A pair of tights with one leg cut out: labelled as the Large Intestine.
  • Two buckets or bowls: one labelled Blood and the other labelled Toilet.
  • A potato masher: labelled as the Teeth.
  • Two sandwich bags: one labelled Stomach and the other labelled Rectum.
  • A pair of scissors.
  • A big sponge: labelled as the Villi.
  • Four containers such as fruit squash bottles, cola bottles or measuring jugs: one labelled Saliva, one labelled Enzymes, one labelled Acid and finally one labelled Bile.

What to Do:

  1. Firstly, make up your four solutions of Saliva, EnzymesAcid and BileSaliva: Add water. Enzymes: Add water, washing up liquid and red food colouring. Acid: Add water and a little bit of malt or white vinegar. Bile: Add water and a few granules of gravy powder.
  2. Collect your favourite foods and add them to the bowl labelled Mouth and using the Teeth, mash the food up into small pieces.
  3. Add the Saliva and some of the Enzymes to help break down the food then using your hands break down the food even further. Your hands represent your Tongue.
  4. Once the food is broken down pour it into the bag labelled Stomach.
  5. Add the Acid and some more of the Enzymes to further break down the food.
  6. Using the scissors cut a hole in the corner of the Stomach bag and let the contents pour into the bowl labelled Small Intestine.
  7. Add more Enzymes and the Bile to the Small Intestine and mix them together.
  8. Using the Villi soak up some of the liquid and transfer this to the Blood.  
  9. Transfer the rest of the contents of the Small Intestine into the Large Intestine.
  10. Squeeze the water out of the Large Intestine and transfer the remaining solid to the Rectum.
  11. Transfer the contents from the Rectum to the Toilet.

Key Points:

  • The Enzymes and Saliva in the Mouth help to break down the Starch.
  • The Acid and Enzymes in the Stomach start the digestion of Protein.
  • The Bile added to the Small Intestine is produced in the Liver and this breaks down Fats.
  • Enzymes in the Small Intestine break down Starch, Proteins and Fats.
  • The Sponge acts like the Villi and absorbs nutrients, which then get transferred to the Blood.


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