What are the two major divisions of the pns?
The two divisions of the PNS (peripheral nervous system) are the sensory neurons and the motor neurons.
Central & Peripheral Edit: I don't think the last person read the entire question. Central (CNS) and Peripheral (PNS) are the two major divisions of the nervous system but the question is asking specifically about the central. Two major division of the central nervous system (structurally) are White matter and Gray matter.
The nervous system is initially divided into the central nervous system (CNS) (brain and spinal cord) and the peripheral nervous system (PNS) (pretty much all nerves and related structures that do not reside in the brain or spinal cord). The PNS is then divided into two two divisions known as the somatic division (voluntary) and the autonomic division (involuntary). The autonomic nervous system is then once more divided into the sympathetic and parasympathetic divisions.