1.immune system function Microglia releases neurotransmitters Neuron produces cerebral spinal Ependymal cell fluid structural component of Astrocyte CNS myelinates axons Schwann cell 2.The brain is the major controlling part of the body. It is composed of the central nervous system and peripheral nervous system of the body. It is assumed that the central nervous system is the major power generating part of the body. The peripheral nervous system is composed of the wire that transmits that energy to the houses. They are two separate systems, but they work together and extensive systems with each other. Component of the central nervous system: