Surprisingly, it wasn't Golgi that finally formulated the neuron doctrine but Santiago Ramon y Cajal , a Spanish neuroanatomist. Cajal stained brains from many different species and meticulously studied the connections of cells in the nervous system. All neurons he identified had three components. A cell body or soma , dendrites , and an axon . The cell body is the metabolic center.
Neurons have many dendrites but usually only one axon.
Axons ranges in size from 0.2 um to 20 um and can extend up to 1 meter. The axon arises from the axon hillock and extends towards the target cell where it divides into fine branches with specialized swellings. These swellings form the presynaptic terminals of cells. The synaptic cleft is a space that separates the presynaptic terminals from the postsynaptic cell . The other cells of the nervous system, Glial cells , can be divided into macroglia and microglia .