First Children Encyclopedia

(Marvins-Underground-K-12) #1
Breathing

How many breaths do you take in a day?


Human body


110


We have to breathe all the


time in order to supply our


bodies with oxygen and


to get rid of carbon


dioxide. We use our


lungs to do this.


The muscle under your
lungs is called the
diaphragm.It moves
up and down as you
breathe.

In and out
Your ribs and diaphragm help you to
breathe. Your lungs fill with air when
you raise your ribcage, then empty out
when you lower it. A muscle called the
diaphragm helps you do this.

Th


e^ di


aphragm


(^) is
Prepare the air
Before the air reaches your lungs it
travels through your mouth and
nose and then goes down your
windpipe. It gets warm and
damp on its journey.
When you breathe
in, your lungs stretch
out and take in lots
of air.
When you breathe
out your lungs
squash down forcing
all the air out.
The air travels down
your windpipe.
This flap shuts
when you eat
so food can’t
go down your
windpipe.
li
ke
a^ trampolin
e.
You breathe in
through your
nose or mouth.
Each lung is a
spongy maze of
tunnels.

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