Explain to a kid how does the heart work?

Your heart is like a pump that keeps blood flowing through your body. It's made of muscle, and it beats to pump blood around. Blood is like a special juice that carries oxygen and nutrients to all parts of your body.

When your heart beats, it pushes blood out to the rest of your body. This blood travels through tubes called arteries. When it gets to the smallest arteries, called capillaries, the oxygen and nutrients from the blood can pass into your body's cells. The blood then flows back to your heart through tubes called veins.

The heart has four chambers: two atria (AY-tree-uh) and two ventricles (VEN-trih-kuls). The atria are the upper chambers, and the ventricles are the lower chambers. When your heart beats, the atria fill up with blood from the body. Then the ventricles squeeze and pump the blood out.

Your heart beats very, very fast. But you don't have to think about making your heart beat. Your body does it automatically!