Oxygen forms about 21% of the air around us. In your body, oxygen forms a vital role in the production of energy in most cells. But if gases can only efficiently diffuse across tiny distances, how does oxygen reach the cells deep inside your body?

Oxygen’s journey through our bodies is surprisingly complex! Enda Butler and TED Ed explain in this video.

Next, watch The Cycle: Carbon and Oxygen and You and They Might Be Giants’ The Bloodmobile. Plus, more videos about the human body.

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