The CNS involves the brain and spinal cord and the PNS involves the body nerves.
For most organism (animals and humans) glucogen is stored in the liver. Glycogen in basically a bundle of glucose. This is like storing energy as the glucogen can be changed back into glucose by a hormone by Glucagon. It breaks down the insoluble glycogen into glucose that can be used in respiration which creates energy.
Respiraton
Glucose+ Oxygen = Water + Carbon Dioxide + ENERGY
(homeostasis) (response to stimuli) (reproduction) growth and development