Are you taking AP Psych? I so know the answer to this.

First off, the parasympathetic NS is designed to facilitate in digestion. You know how sometimes you'll eat a lot of food, then, a few hours later, you'll fall into a deep sleep. While you're sleeping, your parasympathetic NS is taking over.

Secondly, to get to your question, the PNS is also called the craniosacral division of the ANS due to its originating location. The PNS originates from preganglionic neurons in the cranial nerve nuclei of the brainstem or in intermediolateral cell column in the gray matter of the spinal cord -- the location of these preganglionic neurons account for the alternative name for PNS.

I hope that helps.

Yeah, pretty much what she why_wait said.