Cells of nervous tissues are called neurons. Each neuron cell consists of a irregular cell body. From the surface of cell body fine processes arise called dendrites. A long process called axon also arise from the cell body. Sometimes axon is covered by one or two sheath. Then it is called medullated nerve fibre.
The dendrites receive the message or impulses from other neuron or organs. The axon conducts the impulses. The axon also form synapse junction with the dendrites of other neurons.

Fig. Nerve cell with medullated nerve fibre