Know Your Body
Respiratory System
Lungs, airways, and breathing
Official source located — human medical review required.
How it works
Your respiratory system is mainly made of your two lungs. They sit on either side of your heart, inside your chest. Your right lung has three sections and your left lung has two, because your heart takes up some space on the left side. When you breathe in, air travels down into tiny air sacs in your lungs. There, oxygen moves into your blood, and carbon dioxide moves out. Your blood then carries that oxygen to the rest of your body.
Official source located — human medical review required.
Explore three questions
Select a card to open its answer. Select it again to close.
Three key learning points
- The lungs are the main organs of the respiratory system, sitting on either side of the heart.
- Breathing in brings air down to tiny air sacs, where oxygen moves into the blood and carbon dioxide moves out.
- The right lung has three sections and the left lung has two.
Official source located — human medical review required.
Five-question quiz
One question at a time, with feedback after each answer. There is no pass or fail here.
Question 1 of 5
All official sources for this lesson
Source pages
Official source located — human medical review required.
Medical-review checklist for this system
- Confirm the alveoli/gas-exchange explanation is not oversimplified in a misleading way for this age group
- Confirm no wording could be read as guidance for breathing difficulties or asthma symptoms