Through engaging text, readers learn about the human body's circulatory system, which consists of the heart, the blood vessels, and the blood that is pumped through them. Readers discover that the circulatory system transports oxygen and nutrients throughout the body, carries away waste products, sends out disease fighters, and regulates the body's temperature. Topics discussed include the lungs, the kidneys, and diseases that affect the circulatory system. A detailed diagram allows readers to follow a drop of blood through the circulatory system. Ways to maintain a healthy circulatory system are also highlighted. Full-color photos, phonetics, glossary, and index enhance the text.