I've used various versions of the Stick and I agree completely that it seems overpriced when you consider what it *is*, but the darn thing is good at what it *does*, and you'll quickly get over the cost.
In vertebrate species it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body.
The so-called central nervous system consists of the brain and the spinal cord. All other nerves in the body comprise the peripheral nervous system. Efferent nerves carry messages from the central nervous system to all parts of the body (the periphery).