Joe The GI Tract

CONCEPT: General Nutrition



Children learn about the processes of the gastrointestinal (GI) tract through a discussion and worksheet.



After completing this activity, children will be able to:

  • identify two sequential steps of digestion
  • describe why phenylalanine builds up in the body of a person with PKU




  • Ask the children if they know what digestion means. (Digestion is how the body changes the food we eat into something we use to stay healthy and have energy to play.)
  • What does GI Tract mean? (gastrointestinal tract--it's the path our food takes through our body and where the digestion process occurs)

Using a hand drawn diagram of the digestive system or a model of a human torso that comes apart, explain digestion in simple terms.

The mouth chews and breaks down the food. From the mouth the food passes into a long tube called the esophagus. This then empties into the stomach, where the food is broken up more. It is here in the stomach where the protein is broken into smaller pieces called amino acids. Phenylalanine is an amino acid. If you have PKU, the phenylalanine isn't used, so high levels can build up in your body. That is why you need to eat foods that are low in protein. After the stomach, the food goes into the small intestine where a lot of the nutrients are absorbed. Then what isn't absorbed goes into the large intestine where it is eliminated.

Have the children come up to the poster or model and trace the digestive route.

Activity Sheet:
Distribute the worksheet to each child. Allow time for them to complete it individually. Discuss the answers together.



  • Hand drawn poster (use the worksheet diagram as a guide) or model of the digestive system
  • acrobat reader logo Worksheet
    [Answers: starting from the top blank and moving down = mouth, esophagus, stomach, small intestine (right side), large intestine (left side)]
  • Pencils



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