Page 123 - Veterinary Histology of Domestic Mammals and Birds, 5th Edition

Nervous tissue (textus nervosus) 105

5.6 Types of nerve cell (schematic).
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Rough endoplasmic
Nucleoplasm reticulum
Euchromatin

Heterochromatin

Perinuclear space Nucleolus

Neuropil

5.7 Fine structure of the perikaryon of a multipolar neuron within the cerebrum (x5000).

Pseudo-unipolar neurons dendritic axon are part of the peripheral nervous system
The cell bodies of pseudo-unipolar neurons are found in and both are myelinated.
the sensory ganglia of spinal and cranial nerves (Figures Electrophysiologically, the sensory signal bypasses the
5.5 and 5.6). This type of nerve cell develops embryonically perikaryon to pass directly into the dorsal root of the spinal
from a bipolar nerve cell. One of the two cell processes cord. The cell body serves primarily as a potential means
extends into the central nervous system as the axon, while of regenerating nerve cell processes.
the other passes with the anlage of the muscle and skin to
the periphery to become the receptor portion of the cell. Multipolar neurons
During embryonic development, the two processes Multipolar neurons are the most common type of nerve
migrate to one side of the perikaryon and fuse, giving cell (Figures 5.1 to 5.3, 5.6 and 5.7). They develop, for exam-
rise to a single origin. The process that extends to the ple, from neuroblasts of the ventral and dorsal horns of
periphery undergoes internal structural changes, coming the embryonic spinal cord. Several processes extend from
to resemble an axon (dendritic axon). Both the axon and the perikaryon of the neuroblast, beginning to branch at

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