How does your heart keep you alive? How does it pump blood? Why is blood so important? Why do children have heart surgeries? Why is a baby's heartbeat faster before it's born? Why does blood rush to your head when you're upside down? Why can you feel your heart in your head when you're lying still or under water? In this episode of But Why, we're going talking about a very special muscle! It keeps us alive and it has its own special rhythm: the heart. Pediatric oncologist Dr. Jane Crosson from Johns Hopkins Hospital answers questions about the heart.