Your Body Battles a Skinned Knee

Ouch! You know that a skinned knee hurts. But did you know that it's the start of a battle? Your body has to work quickly to protect you from a germ invasion. Nerve cells sound an alarm that you're hurt. Blood cells rush in to fight germs that come in through the scrape. And skin cells make brand-new skin for your knee. Before you know it, your cells have won the battle and you're as good as new. 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.