oxygen (O2) – carbon dioxide (CO2)
nostrils – mouth – lungs – diaphragm
pharynx – larynx (voice box)
trachea (windpipe) – bronchi


What is the function of the respiratory system?

The respiratory system helps us breathe.
The process of breathing is called respiration.
Respiration is the movement of air into and out of the lungs.


The air enters our lungs through the nostrils or the mouth.
The nostrils are the two external openings of the nose.
Through the nostrils we breathe, smell, and sneeze.


We breathe in (inhale) oxygen (O2).
We breathe out (exhale) carbon dioxide (CO2).


The lungs get bigger when we breathe in (inhale).
The lungs get smaller when we breathe out (exhale).


The diaphragm is a strong muscle below the lungs.
It contracts when we breathe in to allow our lungs to fill with air.
It relaxes when we breathe out.

The pharynx opens and the air goes down a tube called trachea.
The trachea is a tube that connects the pharynx and larynx to the lungs.

The trachea is also called the windpipe.
The larynx is also called the voice box.


The air then travels down two tubes called bronchi and enters the lungs.
The lungs take in the oxygen to be carried all over the body.


The oxygen passes from the lungs into the blood.
The blood transports the oxygen to the body’s cells.
The body’s cells need oxygen to keep working.


Carbon dioxide passes from the blood into the lungs.


The body gets rid of carbon dioxide in the air breathed out.
When we breathe out, the carbon dioxide leaves the lungs.

The respiratory system – The Dr. Binocs Show
What happens after we breathe?
How does the air travel inside our body?
Source | Peekaboo Kidz

The respiratory system
To be able to live we must breath.
Source | Happy Learning English

Song – “When You Breathe (Lungs)”
How the lungs take in oxygen to be carried all over your body.
Source | StoryBots

What do the lungs do?
Lesson by Emma Bryce
Animation by Andrew Zimbelman
Source | TED-Ed