In the figure the dendrites are shown in red and axons in blue. The direction of the nerve impulse proceeds from top to bottom.
From the point of view of their structure and especially of their extensions, the following types of neurons are found:
Unipolar neurons have a cell body and one axon. These neurons are not frequently found. Examples: sensory cells of the retina and of the olfactory mucosa.
Bipolar neurons – have a cell body, one dendrite and one axon. Found mainly in sensory structures of the retina and olfactory mucosa.
Pseudounipolar neurons – have a cell body and one extension formed by two continuous parts, one behaves as a dendrite and the other as an axon. They are typically found in the sensory ganglia placed along the the spinal cord and are responsible for conducting nerve impulses of touch, pressure, pain, heat, and cold from the periphery toward the central nervous system.
Multipolar neurons have a cell body, several dendrites, and one axon. They are the majority of neurons of the nervous tissue and are the predominant type of the central nervous system.
