Neurons the building blocks of the brain structure. The central (cns) and peripheral (pns) nervous systems. Pns= network of nerves that connect the cns to the rest of your body. Your brain in made up of network of roughly 100,000,000,000 neurons. Glial cells: they are place-holders, they are nutrient and oxygen suppliers, they are insulators, they are housekeepers. This information is processed in the soma. A major transmitter in both the cns and pns (may play a role in memory and. Acts mainly on inhibitory receptors, helping to create smooth muscle movements (plays a role in parkinson"s disease) Another neurotransmitter that acts mainly on inhibitory receptors (may play a role in schizophrenia and obsessive-compulsive disorder) Curare blocks the action of acetylcholine (a-ce-to-coline) Acetylcholine acts in an excitatory way to activate muscles. With the receptors for acetylcholine blocked, muscles, including the diaphragm cannot be stimulated. No thought, feeling, or action arises from the signals of a single neuron.