So the major difference between our sympathetic and the parasympathetic is in the parasympathetic, both synapses use acetylcholine. In this case, only the pre uses our acetylcholine. The post uses epinephrine. In this case we have a long pre ganglionic and a short post ganglionic. Here we have a short pre ganglionic and a long pre ganglionic. In the sympathetic case it always begins in a spinal cord while in this case it begins either in the brain or in our spinal cord.