A pseudounipolar neuron has one
axon that projects from the
cell body for relatively a very short distance, before splitting into two branches. Pseudounipolar neurons are
sensory neurons that have no
dendrites, the branched axon serving both functions. The peripheral branch extends from the cell body to organs in the periphery including skin, joints and muscles, and the central branch extends from the cell body to the
spinal cord.
In the dorsal root ganglia The cell body of a pseudounipolar neuron is located within a
dorsal root ganglion. The axon leaves the cell body (and out of the dorsal root ganglion) into the dorsal root, where it splits into two branches. The central branch goes to the
dorsal columns of the spinal cord, where it forms
synapses with other neurons. The peripheral branch travels through the distal
dorsal root into the spinal nerve all the way until skin, joint, and muscle.
In most sensory ganglia of cranial nerves Pseudounipolar neurons are found in the sensory ganglia of most
cranial nerves. Specifically the: •
trigeminal ganglion •
geniculate ganglion •
superior ganglion of the glossopharyngeal nerve •
inferior ganglion of the glossopharyngeal nerve •
superior ganglion of the vagus nerve •
inferior ganglion of the vagus nerve Pseudounipolar neurons in cranial nerve sensory ganglia synapse in the
main sensory trigeminal nucleus,
spinal trigeminal nucleus or
solitary nucleus. While the
vestibulocochlear nerve has two ganglia associated with it (
spiral ganglion and
vestibular ganglion), both contain
bipolar neurons, not pseudounipolar.
In the mesencephalic nucleus The mesencephalic nucleus is made up of pseudounipolar neurons which migrated into the
brainstem during embryological development. It is the only location in the
central nervous system where the cell bodies of pseudounipolar neurons are found. ==Function==