Lungs and Breathing

Every cell in your body needs oxygen to work, and breathing is how you get it. When you breathe in, air travels down your windpipe and into your two lungs, which are spongy organs inside your ribcage. Take a deep breath now and feel your chest grow bigger!

The air you breathe is a mixture of gases. The one your body wants is oxygen. Your cells use oxygen like a fire uses air, to turn food into energy. In return, your cells make a waste gas called carbon dioxide, which you need to get rid of by breathing out.

Inside each lung are millions of tiny air sacs called alveoli. They are wrapped in tiny blood vessels. Oxygen from the air passes through their thin walls into your blood, and waste carbon dioxide passes back the other way to be breathed out. This swap happens with every single breath.

How does air get in and out? The hero is your diaphragm, a dome-shaped muscle just below your lungs. When it contracts and flattens, it makes more space, so air rushes in. When it relaxes back into a dome, it pushes air out. Put a hand on your tummy and feel it move as you breathe.

When you exercise, your muscles need more oxygen, so you breathe faster and deeper. That is why you puff and pant after running — your body is grabbing extra oxygen and clearing out extra carbon dioxide as quickly as it can. It is a sign your lungs are doing a great job.

You can look after your lungs by staying active, which keeps them strong, and by breathing fresh clean air. Coughing and sneezing are clever tricks your body uses to blast out dust and germs and keep your airways clear.