Your body is an amazing thing. When it sleeps it does not shut down. The brain is still processing information it gathered throughout the day, "disposing" of the unimportant information and reviewing the important things. Your body also shifts gears to allow it to concentrate on the less important things that it ignores for much of the day... The autonomic nervous system shifts its energy from making sure that you are not attacked by a tiger or hit by a car, to digestion and self-repair. The heart still beats, you still breathe, and your mind dreams beautiful dreams. Have you ever been dreaming and something from the outside world like an alarm clock or your mother's voice becomes part of your dream for a few seconds before you wake up and discover that it was actually something that you were hearing (while asleep). Your brain is so keenly aware, even while you sleep that in a split second it can process that sound and make sense of it and bring it into your dream that is already in progress... No, your whole body does not shut down when you sleep.
