2. How does air get into and out of our lungs?

Knowledge

Breathing is physically getting air into the lungs and out of the lungs. Your lungs are not muscles and cannot move or change to make this happen.

Instead breathing happens because the intercostal muscles and the diaphragm muscle contract and relax.

You breathe in when the diaphragm contracts and moves down and the intercostal muscles contract and move the ribs up and out. These movements cause an increase in the space in the chest.

Another way of saying this is the same amount of air inside the lungs is now in a larger space. Air then rushes in through the mouth and trachea to fill the space.

We breathe in to get air with lots of oxygen into our lungs.

You breathe out when the diaphragm relaxes and moves up and the intercostal muscles relax and move the ribs in and down. These movements cause a decrease in the space in the chest. Another way of saying this is the same amount of air inside the lungs is now in a smaller space. Air needs to rush out as there is not space for some of the air inside the lungs so some of it needs to move out.

We breathe out to get air that contains lots of toxic carbon dioxide out of our lungs.

Vocabulary

Breathing: Letting air in and out of the lungs.

Diaphragm: Large sheet of muscle under the lungs that is responsible for breathing.

Exhale: When the diaphragm and intercostal muscles relax, air flows out of the lungs.

Inhale: When the diaphragm and intercostal muscles contract, air goes into the lungs.

Intercostal muscles: Muscles found in between the ribs that help with breathing.

Ribs: Bones that form a cage around the lungs to protect it.

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