"Did you know that if all your blood vessels were laid out end-to-end, they would stretch all the way around the world, not just once but twice? Not only that--you are made up of millions of cells, many miles' worth of nerve fiber, and more than 20 feet of intestine. The human body is a truly amazing machine, capable of growth and self-repair. In this book, you can find out all about your insides and how they work."--Provided by publisher.