101 facts about the human body that will surprise and amaze you. Did you know: That you shed approximately six hundred thousand skin particles every hour? That yawning cools the brain? Or that the appendix plays an important role in gut health? The human body is a marvel -- one that can grow, repair itself, and last for eighty to ninety years. In 101 Fascinating Human Body Facts , Dr. Kieran Murphy and Anya Murphy explain the functions of this extraordinary machine, from how we process memories to how the liver works and from why we fart to why we can't tickle ourselves.