NERVE TISSUE
Figure 1­15
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Nerve tissue is located in the central, peripheral, and autonomic nervous systems. It consists of nerve cells (neur-
ons), their cytoplasmic processes (neurites), and supporting (glial) cells. There are two types of neurites: dendrites
LLC.
and axons. Neurons and their processes exercise control over body functions and integrate a great amount of in-
formation. Dendrites send the information toward the neuronal cell body, the area of the neuron that contains the
Not
nucleus, whereas axons transmit the information away from the cell body.
to
be
redistributed
In histologic sections, it is often difficult to visualize the neuron and its processes. The neuron shown in this image
has a round nucleus with a distinct nucleolus (arrowhead). The nucleus and surrounding cytoplasm constitute the
cell body, or perikaryon. This cell has at least three cytoplasmic extensions, or neurites (arrows). One is probably
an axon and the others are dendrites. A neuron has only one axon and several dendrites. Neurons are encased in
or
support cells, connective tissue, and processes from other cells in an area called the neuropil. The neuron shown
modified
here is located in the spinal cord, part of the central nervous system. The brain and spinal cord form the central
nervous system. The peripheral nervous system is the division outside of the brain and spinal cord.
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15

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