"What is that thing pumping in your chest to help you run, dance, play, and live your life? Thump-thump, thump-thump. It's your heart! With every beat, your heart pumps blood through your body to help you keep going. It sends out oxygen and takes out the trash. And that's just the beginning! Explore what's inside you with . . . text, . . . pictures, and . . . illustrations"--Provided by publisher.