There are two aspects to consider to understand the difference between the central and peripheral nervous system. Anatomically speaking, the CNS is made up of the brain and the spinal cord; the PNS is made up of all the nerves travelling from the CNS to all the organs in your body, from the skin on your scalp to the tip of your toes. From a functional perspective, the CNS is the core processing unit, receiving inputs, processing them and initiating an output signal. The PNS is the carrier of this input and output information, from the CNS to the rest of your body. There are also two aspects to the PNS, a motor and sensory system. So the input signals are made up from the sensory information that the PNS picks up, and the output signals eventually lead to motor functions transmitted to various muscles.