Every person and animal needs to breathe to stay alive. Your respiratory system is the group of organs (body parts) that helps you breathe. You have two lungs in your chest. They are full of air, like balloons. You wouldn’t want them to pop, so twelve bones called ribs make a cage around your lungs to keep them safe.
When you breathe, air comes into your body through your mouth and nose. The air goes down your windpipe (a tube in your throat) and then into two tubes or bronchi. One bronchus goes into each lung. The tubes get smaller and smaller like branches on a tree until they get to tiny air sacs. These air sacs, called alveoli, take oxygen (a special kind of gas that your body needs in order to get energy) from the air you breathe to all the different parts of your body.