This enthralling look at the workings of the cardiovascular system introduces young readers to the human heart and its function. Along with the heart’s atria and ventricles, the book explains the circulatory system and how the blood and its pathways operate. Readers get an in-depth look at red and white blood cells, platelets, plasma, blood pressure, blood types and donors, and how the lymphatic system works with the rest of the body’s organs and tissues. Vocabulary boxes explain new words, Think About It sections pose questions for readers’ consideration, and Compare and Contrast sidebars engage readers’ minds.