1. Living Systems
Investigation 3, Part 3 –
Respiratory Systems

2. Focus Question Why do people breathe?
Living Systems, 3.3: Respiratory Systems
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3. Respiratory System
The lungs are the most important part of the respiratory system. The respiratory system is the system you use for breathing. Your lungs are connected to the environment by a system of tubes and openings. The lungs rest in a chamber inside your chest. The chamber has a large, flat, arched muscle at its bottom edge. The muscle is your diaphragm. When the diaphragm muscle contracts, air is pulled into your lungs, and you inhale. When the muscle relaxes, air flows out of your lungs, and you exhale.
Living Systems, 3.3: Respiratory Systems
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4. Reading in Science Resources
Living Systems, 3.3: Respiratory Systems
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5. View the video
Living Systems, 3.3: Respiratory Systems
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6. Vital Capacity
Vital capacity is the maximum amount of air you can exhale on one breath. Why do you think vital capacity is considered a runner's secret weapon?
Living Systems, 3.3: Respiratory Systems
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7. Vital Capacity Investigation
Use the lung volume bag to measure your vital capacity. Work in pairs.
Materials:
2 lung volume bags
4 mouthpieces
2 rubber bands
To measure how much air is in the volume tube:
Grasp the bag just past the mouthpiece.
Wind the bag around your hand. The captured air will be pushed toward the closed end of the bag.
Read the volume of air from the markings on the bag.
Empty the bag to make it ready for your next trial or the next user.
Living Systems, 3.3: Respiratory Systems
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8. Vital Capacity Investigation
Measure and record your vital capacity (lung volume) three (3) times.
Calculate your average vital capacity.
Living Systems, 3.3: Respiratory Systems
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9. Vital Capacity Class Data
Living Systems, 3.3: Respiratory Systems
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10. Sense-Making Discussion
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11. Vocabulary Review
respiratory system the system of lungs and connecting tubes that transports oxygen to the red blood cells and gets rid of carbon dioxide diaphragm a large muscle between the chest and abdomen that is involved in breathing vital capacity the organ in animals where gases, such as oxygen and carbon dioxide, pass between the atmosphere and the blood alveoli the air sacs at the ends of the bronchioles in the lungs
Living Systems, 3.3: Respiratory Systems
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12. Clean Up! Disassemble the lung volume bags.
Recycle the mouthpieces and lung volume bags.
Return all other materials to the materials station.
Living Systems, 3.3: Respiratory Systems
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13. Focus Question Why do people breathe?
Discuss the focus question in your group and then respond on your own.
Living Systems, 3.3: Respiratory Systems
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14. Reading in Science Resources
Living Systems, 3.3: Respiratory Systems
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15. Wrap-Up
Use your three self-stick strips to mark the three most important things you've learned in this investigation. Use a highlighter or colored pencils to highlight key points. Discuss in your groups the ideas you have marked.
What are the key points in this investigation?
Living Systems, 3.3: Respiratory Systems
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16. Investigation Guiding Question
How do plants and animals get nutrients to all of the cells?
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Photo credits:
Cover slide: © photovideostock/Shutterstock
Notebook image: © photastic/Shutterstock TM
Living Systems, 3.3: Respiratory Systems