Science Common Sense

936 - How do our lungs help us breathe, and how does oxygen get into the blood?

Our lungs are like two big balloons in our chest. They help us breathe by filling up with air when we inhale (breathe in) and emptying out when we exhale (breathe out).

Here's how oxygen gets into the blood:

1. We inhale air through our mouth or nose into our lungs.
2. The air fills the tiny air sacs in the lungs, called alveoli.
3. In the alveoli, oxygen passes through thin membranes into the bloodstream.
4. The oxygen then sticks to a special protein called hemoglobin in our red blood cells.
5. The oxygen-rich blood is carried to all parts of the body, giving energy to our muscles and organs.

When we exhale, the opposite happens: our body sends back the "bad" air (with carbon dioxide) out of the lungs and out of the body.