Neurons

Neurons are the conducting cells of the nervous system. A typical neuron consists of a cell body, containing the nucleus and the surrounding cytoplasm; several short radiating processes (dendrites); and one long process (the axon), which terminates in twiglike branches and may have branches projecting along its course.

Cell Body

In many ways, the cell body is similar to other types of cells. It has a nucleus with at least one nucleolus and contains many of the typical cytoplasmic organelles. It lacks centrioles, however. Because centrioles function in cell division, the fact that neurons lack these organelles is consistent with the amitotic nature of the cell.

Dendrites and Axons

An axon is a long, hair-like extension of a nerve cell that carries a message to another nerve cell.

Dendrites are thread-like extensions of the cytoplasm of a neuron that receive signals from other neurons. Typically, as in multipolar neurons, dendrites branch into treelike processes, but in unipolar and bipolar neurons, dendrites resemble axons.

Glial Cells

Glial (Neuroglial) cells do not conduct nerve impulses, but instead, support, nourish, and protect the neurons. Glial cells are far more numerous than neurons and, unlike neurons, are capable of mitosis.

For more information about anatomy of brain and CNS, go to the Nervous System Unit of the Anatomy and Physiology module on this Web site.