The spinal cord runs from the base of the skull all the way down the spine to the "tail bone." The neurons are found in an H-shaped space within the spinal vertebrae. There are motor pathways coming down from the brain and sensory pathways going up to the brain. Sensory nerves enter into the back parts (dorsal roots) of the "H," while motor neurons exit the forward parts (ventral roots) of the "H." Interneurons often connect these sensory and motor neurons. Besides sending messages up and down to and from the brain, the spinal cord has another very important function: Reflexes. In fret, in very simple animals, that is the main function of the cord. Basically, a reflex is the connection of sensory neurons, via interneurons, to motor neurons. For example, there are pair sensors in your fingers. If you hold your finger over a flame for a period of time, the pair will trigger motor neurons to pull your finger away. It is true that you can over-ride thi: reflex with "will power," but as the example intentionally shows, it isn't easy! Reflexes do much more than just get your finger out of the fire: A great deal o; movement is accomplished through reflexes. Even brand new babies already have the necessary reflexes for walking: If you hold a baby and gently touch its feet to the floor, i' will start making step-like movements! All that is needed is the muscle strength to Stanc and, of course, a lot of practice.