The central (cns) and peripheral (pns) nervous systems. Pns = network of nerves that connect the cns to the rest of your body. Neurons: the building blocks of the brain. Your brain is made up of a network of roughly 100 000 000 000 neurons. Glial cells (1) place-holders. (2) nutrient and oxygen suppliers. (3) insulators. (4) house-keepers. That information is processed in the soma. The soma sums the total excitatory and inhibitory input it receives and if the excitatory input is above a certain threshold, the soma generates an action potential. That action potential travels down the axon to the terminal buttons, where it stimulates the release of chemicals that travel to the next neuron. They only happen once sufficient stimulation is achieved. Are fundamentally the same, regardless of the message" they carry. Although action potentials are all-or-nothing", the neural system can code for intensity by the frequency of action potentials.