Multipolar neurons are the most common type of neuron in humans. There is usually one axon and at least two dendrites. There is a subtype seen in the CNS called the “anaxonic neuron” that has no obvious axon. The cell still has projections but any of the projections can act as an axon at any given point in time. There are other classifications of neurons that depend on where the nerve cell is located in the body but these are less commonly seen.
TYPES OF GLIAL CELLS Glial cells are the type of cell found in the nerve tissue that act as supporting cells to the neurons. They are also referred to as neuroglial cells or “neuroglia.” There are six types of neuroglia (which were described in Chapter 2). Figure 61 shows what the different neuroglial cells look like:
Four of these cell types are seen in the CNS and two are seen in the PNS. A brief review of these cells is included here: •
Astrocyte—a supportive cell
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Oligodendrocyte—a cell for insulation and myelination
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Microglia—cells for phagocytosis and immune surveillance
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