How do humans breathe?

Follow me please class.

We're in the gym to look at how humans breathe.

Every living thing needs oxygen to survive, and the point of breathing is to get oxygen inside the body and to get rid of carbon dioxide.

But how does it all work?

Let’s use our virtual biology headsets to find out.

Here we are at the entrance to the lungs, which are working hard to take in lots of oxygen.

When humans exercise, they breathe heavily, as their muscles need even more oxygen than usual.

When a human breathes in, their chest muscles move upwards and outwards and the diaphragm muscle under their lungs moves down.

This creates a bigger space in the chest and the change in pressure makes air flow in through the nose and mouth, come down the windpipe and into the lungs.

When humans breathe out, their diaphragm and chest muscles relax, making the space in the chest smaller, which pushes the air out again.

When air goes down into the lungs, it passes through smaller and smaller tubes and ends up in tiny air sacs called alveoli.

Oxygen passes through the walls of the alveoli and enters tiny blood vessels.

The blood vessels carry oxygen around the body to where it’s needed.

Carbon dioxide – a waste gas that the body needs to get rid of – passes from the blood vessels into the alveoli and gets breathed out into the air.

Wheee!

I think I could use some exercise myself.

Stand back kids, let me show you how it’s done.

Oh, ooh, ooh…

Oooo!

Aaargh!

Eeee!