Illustrations and simple text help young readers learn about the heart and the lungs.

Describes the structures and functions of the respiratory and circulatory systems, including the lungs and airways, blood cells, the heart, arteries, veins, capillaries, pulmonary circulation and the lymphatic system.

Traces the route that blood takes through the heart to the lungs and tissues, and back. Describes how the heart and lungs fine-tune their actions to supply the power and oxygen needed in any situation.