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🫁 Gas Exchange and Breathing

Follow air deep into your lungs and discover how oxygen and carbon dioxide swap places by diffusion across the alveoli.

lessons

~15 min

to learn

🔬 Science

subject

Teens

level

Start the course →

What you’ll learn

The Breathing SystemDescribe the path of air through the breathing system and how the diaphragm and ribs move air in and out.Breathing supplies oxygen and removes carbon dioxide. Air passes from the nose down the trachea, through the bronchi and bronchioles, to the alveoli. The diaphragm and rib muscles change the chest size to draw air in and push it out.
Gas Exchange in the AlveoliExplain how gas exchange happens in the alveoli by diffusion and why alveoli are well adapted for it.Gas exchange happens in the alveoli by diffusion: oxygen diffuses from the air into the blood and carbon dioxide diffuses the other way. A huge surface area, walls one cell thick, and a rich blood supply make the exchange fast and efficient.

Questions this course answers

Why do humans need to breathe?

Breathing supplies oxygen for respiration and removes carbon dioxide.

What is the correct order air travels when you breathe in?

Air flows nose, trachea, bronchi, then alveoli.

Which muscle flattens to help draw air into the lungs?

The diaphragm flattens to enlarge the chest and pull air in.

By what process do gases move across the alveolus wall?

Gases cross the alveolus wall by diffusion, high to low concentration.

What makes alveoli so good at gas exchange?

A large, thin, moist surface makes diffusion fast.

Compared with the air you breathe in, the air you breathe out contains:

Exhaled air has more carbon dioxide and less oxygen.

Grounded in trusted sources

BBC Bitesize
Britannica
KidsHealth (Nemours)
NHS

Every Wunder lesson is built from real, reputable sources — never invented.

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