Neurons make up the conducting cells of our nervous system. Most neurons have a cell body, a nucleus, cytoplasm, dendrites and axons (or processes). A neuron can be be classified according to how many processes extend from its cell body.
Dendrites and Axons
Dendrites are the branch-like extensions of the cell's cytoplasm that receive signals from other cells. Axons are the long, thin extensions that carry nerve signals to other cells.
A neuron with more than two cell body processes is called a multipolar neuron. The dendrites of a multipolar neuron tend to look like tree branches.
A neuron with two cell processes is called a bipolar neuron. The cell bodies of this type of neuron can be found in the olfactory epithelium, retina, and the vestibular and cochlear ganglia. These neurons have dendrites that resemble axons.
Most neurons in the human (and in all mammals) are multipolar, while bipolar neurons are less common.
Bipolar neurons tend to be round or oval in their appearance. Multipolar neurons come in a variety of different shapes, many of which are so distinctive that they have special names, such as purkinje, pyramidal, granular, and motor neurons.
- Photo Credit blue brain image by John Sfondilias from Fotolia.com autumn image by Egle Siskauskiene from Fotolia.com