A pseudounipolar neuron (pseudo - false, uni - one) is a sensory

Sensory neuron

Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...

 neuron

Neuron

A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

 in the peripheral nervous system

Peripheral nervous system

The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...

. This neuron contains an axon that has split into two branches; one branch runs to the periphery and the other to the spinal cord.

Central and peripheral axons of a pseudounipolar neuron

By definition, a pseudounipolar neuron has one axon with two branches: central and peripheral. These axonal branches should not be confused with dendrites. Pseudounipolar neurons do not have dendrites. Each axon has a peripheral branch (from the cell body to the periphery: skin, joint and muscle) and a central branch (from the cell body to spinal cord).

Anatomy

The soma (cell body) of each pseudounipolar neuron is located within a dorsal root ganglion

Dorsal root ganglion

In anatomy and neuroscience, a dorsal root ganglion is a nodule on a dorsal root that contains cell bodies of neurons in afferent spinal nerves.-Unique unipolar structure:...

. 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 posterior (dorsal) horn of the spinal cord, where it forms synapse

Synapse

In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell...

s with other neurons. The peripheral branch travels through the distal dorsal root

Dorsal root

In anatomy and neurology, the dorsal root is the afferentsensory root of a spinal nerve.At the distal end of the dorsal root is the dorsal root ganglion, which contains the neuron cell bodies of the nerve fibres conveyed by the root.If the dorsal root of a spinal nerve were severed it would lead...

into the spinal nerve all the way until skin, joint, and muscle.

Signal Pathway

These neurons have sensory receptors on skin, joints, muscles, and other parts of the body. The signal is conducted through the axon to the dorsal root ganglion's cell body, then through the axon and ending at the sensory nuclei in the posterior horn of the spinal cord.

External links

• Diagram at ccccd.edu