Biology Grade 6-8

Science: The Respiratory System

How the body takes in oxygen and removes carbon dioxide

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Science: The Respiratory System

How the body takes in oxygen and removes carbon dioxide

Biology - Grade 6-8

Instructions: Read each problem carefully. Answer in complete sentences and show your thinking when needed.
  1. 1
    Diagram of air entering the lungs and gases being exchanged.

    What is the main job of the respiratory system in the human body?

  2. 2
    Air path from nose and mouth through the airway into the lungs.

    List the path air follows as it enters the body through the nose or mouth and travels to the lungs.

  3. 3
    Trachea shown as a ringed airway carrying air toward the lungs.

    What is the function of the trachea?

  4. 4
    Close-up of alveoli exchanging gases with surrounding capillaries.

    Explain what happens in the alveoli.

  5. 5
    Many thin-walled alveoli surrounded by capillaries for gas exchange.

    Why are alveoli well suited for gas exchange?

  6. 6
    Diaphragm moving downward beneath the lungs as the lungs expand.

    Describe the role of the diaphragm in breathing.

  7. 7
    Comparison of inhaling with expanded lungs and exhaling with smaller lungs.

    What is the difference between inhaling and exhaling?

  8. 8
    Lungs and heart connected by blood vessels showing gas exchange.

    How do the respiratory system and circulatory system work together?

  9. 9
    Nasal cavity filtering, warming, and moistening incoming air.

    Name two ways the nose helps prepare air before it reaches the lungs.

  10. 10
    Healthy and smoke-damaged lungs shown side by side.

    How can smoking damage the respiratory system?

  11. 11
    Rib muscles and diaphragm moving to expand the lungs.

    A student says that the lungs are muscles that push air in and out. Explain why this statement is incorrect.

  12. 12
    Running student with lungs and heart working harder during exercise.

    Why does your breathing rate usually increase during exercise?

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