Bipolar cell

A bipolar cell is a type of neuron which has two extensions. Bipolar cells are specialized sensory neurons for the transmission of special senses. As such, they are part of the sensory pathways for smell, sight, taste, hearing and vestibular functions.

The most common examples are the bipolar cell of the retina, and the ganglia of the vestibulocochlear nerve. When used without further detail, the term usually refers to the retinal cells.

Bipolar cells are also found in the spinal ganglia, when the cells are in an embryonic condition.

They are best demonstrated in the spinal ganglia of fish.

Sometimes the extensions, also called "processes", come off from opposite poles of the cell, and the cell then assumes a spindle shape; in other cells both processes emerge at the same point.

In some cases where two fibers are apparently connected with a cell, one of the fibers is really derived from an adjoining nerve cell and is passing to end in a ramification around the ganglion cell, or, again, it may be coiled spirally around the nerve process which is issuing from the cell.