The Circulatory System[edit | edit source]
The circulatory system moves blood around your body. This blood carries nutrients and oxygen and gives it to all of the cells in the body. It also carries signals called hormones that help the body work together.
The major organ of the circulatory system is the heart, which pumps the blood. Blood goes away from the heart in tubes called arteries and comes back to the heart in tubes called veins. The smallest tubes are called capillaries.