A neuron in which there is no myelin sheath surrounding the axon.
The unmyelinated neuron pertains to any of the neurons without myelin sheath (a sheath for the rapid conduction of action potential). Compared to myelinated neurons, unmyelinated neurons are slower in terms of conducting impulses and are found in the peripheral nervous system (especially visceral nervous system) and the gray matter of the nervous system.
Word origin: un– (not) + myelinated + neuron
Compare: myelinated neuron
See also: myelin