Journeys: Heart. Stop 4

Capillary

We're in the thinnest blood vessels, the capillaries. The lungs are on the left, a muscle on the right. Tap the oxygen bubbles!

Red balls float in the blood. They take oxygen in the lungs and carry it through the heart to the muscles.

The oxygen has arrived in a muscle cell. With it, the cell makes the power for running and jumping.

Blood is drawn blue once it has given away its oxygen. Really it's dark red.

Wait until a blue ball floats under the air sac.

These are real blood cells under a microscope. One little drop holds hundreds of millions of them!