Description How many times does your heart beat per minute? That depends on what you are doing. This informative book about the heart shows how blood pumps throughout the body. It explores the work of the atria and ventricles as they pump throughout the chambers and valves, bringing oxygen to the body's system. Colorful photographs and diagrams help make the concepts clear for readers, while a final activity encourages them to put their new knowledge to use as an authentic learning exercise.