Anatomy PhysiologyYour Lungs Fill With Air When You Breathe In
Medi the cheerful guide stands in a bright classroom, holding two soft balloon-shaped models of lungs. Medi slowly breathes in and the balloons puff up big, then breathes out and the balloons shrink down small, smiling wide at the children watching.
- Identify the lungs as body parts found inside the chest.
- Explain what happens to the lungs when you breathe in and when you breathe out.
- Compare the size of the lungs when they are full of air versus when the air has left.
- Demonstrate breathing in and breathing out using their own body.
Key terms
- lungs
- Two soft body parts in your chest that fill with air.
- breathe in
- To pull air into your lungs so they get bigger.
- breathe out
- To push air out of your lungs so they get smaller.
- air
- The invisible mix of gases you take in when you breathe.
Two Lungs in Your Chest
You have two lungs, one on the left side and one on the right side of your chest. They are soft and spongy, not hard like bones. Your curved rib bones make a cage around your lungs to keep them safe. If you put your hands on your chest, you can feel it move as your lungs fill and empty.
Breathing In and Out
When you breathe in, air rushes into your lungs and they puff up bigger, just like a balloon filling with air. When you breathe out, the air flows back out and your lungs shrink down smaller again. This in-and-out movement happens over and over and is how you keep fresh air moving through your body.
Always Working
Your lungs work every minute of every day, even while you sleep, because your body needs a steady supply of fresh air. You usually breathe without thinking about it, but you can also take a big breath on purpose. Whether you notice it or not, your lungs never stop filling and emptying to keep you going.
Worked examples
Tell what happens to your lungs when you breathe in.
- Breathing in pulls air into the lungs.
- Air filling the lungs makes them puff up.
- So the lungs get bigger when you breathe in.
Answer: Your lungs get bigger because air fills them up.
Decide what happens to your lungs when you breathe out.
- Breathing out pushes air out of the lungs.
- With less air inside, the lungs shrink.
- So the lungs get smaller when you breathe out.
Answer: Your lungs get smaller because the air leaves them.
Activity
Help Medi sort each picture into the right box — Breathing IN or Breathing OUT.
Practice
How many lungs do you have, and where are they in your body?
Why do your lungs get bigger when you breathe in and smaller when you breathe out?
Common mistakes to avoid
- Lungs get bigger when you breathe out.Lungs get smaller when you breathe out because the air leaves them, and bigger when you breathe in.
- Your lungs are in your belly.Your lungs are in your chest, one on each side, protected by your rib bones.
Check your understanding
What happens to your lungs when you breathe IN?
Where are your lungs inside your body?
A friend says your lungs get bigger when you breathe OUT. Are they right?
Recap
You have two soft lungs in your chest, one on each side. When you breathe in, air fills them and they get bigger; when you breathe out, the air leaves and they get smaller. Your lungs never stop working.
Reflect
Why do you think it is helpful that your lungs keep working even when you forget to think about breathing?