CRRAACK! Breaking a bone hurts! But did you know that it's the start of a battle for your body to heal itself? That ache happens because damaged nerve cells send out a cry for help. In response, red blood cells rush in to bring oxygen and nutrients. White blood cells clean up the dead bone and muscle cells. Blood also brings fibroblast cells. They build a sort of scaffolding around the break so that new bone will fill in. And stem cells arrive to transform themselves into cells that will make brand-new bone. The whole area becomes an active construction site as your body battles the damage and heals itself. Get a close look at this body battle with comic illustrations and ground-breaking photomicrographs. The photomicrographs magnify the actual cellular processes tens of thousands of times, offering you a front-row seat for all the action.