Your hardworking heart started beating eight months before you were born and continues to beat about one hundred thousand times a day. "By the time you're seventy years old, it will have beaten about 2.5 billion times." Find out the story behind each beat on a journey through the body's circulatory system.
This resource is supported by the Institute of Museum and Library Services under the provisions of the Library Services and Technology Act as administered by State Library of Iowa.