Take a Breather
Take a Breather
Take a deep breath. Can you feel your chest lifting and
expanding as you inhale? Now let the air out. Can you feel
your chest move back down when you exhale? You have
probably noticed this movement before. But have you
thought about what is happening inside your body when you
breathe?
All of the cells in your body need oxygen. And when cells use
oxygen, they make a waste product called carbon dioxide.
It is the job of your respiratory system to bring oxygen
from the air into your body and push carbon dioxide out of it.
Muscles for Breathing
When you breathe, certain muscles contract
and relax. This movement causes your lungs
to fill with air and to release air. The most
important muscle for breathing is called the
diaphragm.
The diaphragm is a sheet of muscle that lines
the area under your lungs. When the
diaphragm contracts, it pulls downward.
This causes the space in your chest to get
bigger. It helps pull air into your lungs.
When your diaphragm relaxes, it moves back
up. This forces air to move out of your lungs.
The diaphragm contracts and relaxes over
20,000 times each day!
Other muscles help you breathe, too.
You might be able to feel these muscles between your ribs.
When these muscles contract, your ribs move up and out.
This also helps you inhale by making the space in your chest
bigger. When these muscles relax, it helps you exhale.
The muscles between your ribs contract and relax at the
same rate as your diaphragm to help you breathe.
Autonomic Process
Breathing is autonomic. That means you don’t have to think
about it for it to happen. And it’s a good thing, too, because
you need to breathe even when you sleep. Your body needs a
constant supply of oxygen in order to live.
Discovery Education Science
© 2007 Discovery Communications, LLC
Page 1 of 2
Take a Breather
And your respiratory system always knows how hard it
should be working. When you exercise, you breathe faster
because your cells need more oxygen. And when you rest,
you breathe more slowly because your cells don’t need as
much oxygen. So sit back, relax, and take a breather. Your
respiratory system will take care of the rest!
Discovery Education Science
© 2007 Discovery Communications, LLC
Page 2 of 2