Objective
By the end of this lesson, you will be able to understand the basics of the human body's digestive and excretory systems.
Materials and Prep
- Whiteboard or large paper
- Markers or colored pencils
- Printed diagrams of the digestive and excretory systems
No prior knowledge is required for this lesson.
Activities
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Draw and label the digestive system:
Using the whiteboard or large paper, draw the digestive system and label its parts. Start with the mouth, esophagus, stomach, small intestine, large intestine, and end with the rectum. Discuss the functions of each part as you draw and label them.
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Trace the path of food:
Using the printed diagrams, trace the path of food through the digestive system. Start with the mouth and follow it all the way to the rectum. Discuss the role of each organ in breaking down and absorbing nutrients from the food.
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Learn about the excretory system:
Discuss the excretory system and its role in removing waste from the body. Explain the functions of the kidneys, bladder, and urethra in filtering and eliminating waste as urine.
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Quiz time:
Give a short quiz to test your understanding of the digestive and excretory systems. Ask questions about the different organs and their functions. Use the diagrams to help you answer the questions.
Third Grade Talking Points
- "The digestive system helps our bodies break down the food we eat so we can get energy and nutrients."
- "The mouth is where digestion begins. We chew our food to break it into smaller pieces."
- "The stomach is like a mixer. It mixes the food with special juices that help break it down even more."
- "The small intestine is where most of the nutrients from our food are absorbed into our bloodstream."
- "The large intestine absorbs water from the remaining food waste, and then the waste moves to the rectum."
- "The excretory system helps our bodies get rid of waste materials that our cells produce."
- "The kidneys are like filters. They remove waste and extra water from our blood to make urine."
- "The bladder stores the urine until we are ready to go to the bathroom."
- "The urethra is the tube that carries the urine from the bladder out of our body when we pee."