Video narration
How does your heart send blood around your body? Like a pump bottle, squeezing pushes liquid forward; one-way valves stop backward flow. Your heart muscle contracts rhythmically as two pumps. Oxygen-poor blood from your body goes to one side, then the lungs. There, it picks up oxygen and returns to the heart. The other side sends oxygen-rich blood around your body. Body, heart, lungs, heart, body-repeating. That's two pumps: one to lungs, one to body.