Exchange and organ systems

What you'll learn

1. 1

   Your lungs are like a giant air balloon 🎈 — they take in oxygen and let out carbon dioxide. This happens in tiny air sacs called alveoli.

2. 2

   Here's a diagram of an alveolus — a tiny grape-like sac surrounded by blood vessels.

3. 3

   Drag the oxygen and carbon dioxide molecules to show how gas exchange works in the alveolus.

4. 4

   Let's trace the path of an oxygen molecule from the air into your blood.

5. 5

   What gas moves FROM the blood INTO the alveolus to be breathed out?

6. 6

   True or false: The walls of the alveoli are very thin to help gases move quickly.

7. 7

   Which organ system works with the respiratory system to deliver oxygen to all your cells?