7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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peripheral nerve
Peripheral nerves include: cranial
nerves, spinal nerves.
It is made up of bundle of nerve
fibers, both myelinated and
unmyelinated.
On naked eye examination, it
appears whitish and glistening
because of their myelin and
collagen content.
Examples: median nerve, ulnarnerve, sciatic nerve
7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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peripheral nerve (cont.)
Epineurium: it is sheath of dense
irregular C.T. around peripheral
nerve.
Perineuriun:
it is C.T sheath around each fascicle
or bundle of nerve fibers.
This is made by many concentric
layers of epitheloid cells joined
together by tight junctions .
Perineurium acts as a barrier to the
passage of materials.
endoneurium: it is thin layer of
C.T. around each nerve fiber. It is
composed of delicate collagenous
and reticular fibers and
fibroblasts.
7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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peripheral nerve (l.s.)
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7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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peripheral nerve- identification points
Bundles of nervefibers
Myelin sheath isseen as unstainedarea
Endoneurium,perineurium andepineurium isvisible
7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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GANGLIA
Ganglia: It is collection ofnerve cell bodies outside theCNS
Ganglia are ovoid structuresassociated with peripheralnerve.
microsopically and functionallythe ganglia are of two types: Craniospinal (sensory) ganglia
Autonomic ganglia Common features of both
types of ganglia: Both types of ganglia have C.T.
capsule.
The body of each ganglion cellis surrounded by satellite cells
7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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Cranio Spinalganglia
Cranial ganglia
Spinal ganlia (dorsal root ganglia)
C.T. Capsule
Ganglion cells are pseudounipolarneurons ***
Each cell has a single process whichbifurcates in a T-shaped manner.
One of the two processes acts asdendrite and passes to peripheryto terminate at a receptor organ
The othe branch acts as axon andpasses to CNS.
The nerve impulses pass from theperiphery to CNS, bypassing thecell body.
So the cell body form no synapsesand performs an exclusivelytrophic function.
7/31/2019 6. Lecture on the Histology of Peripheral Nerve and Ganglia by Dr. Roomi
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Cranio Spinal ganglia (cont.)
The nerve cell bodies arearranged as groups in theperipheral zone of theganglion.
Each ganglion cell issurrounded by a singlelayer of low cuboidal cellsare called as satellite cells
Central zone of the
sensory ganglion showsgreat predominance ofnerve fibers
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Dorsal root ganglion
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Dorsal root ganglion- how to draw it!
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Autonomic Ganglia
These ganglia areassociated withsympathetic andparasympathetic ANS.
These ganglia containmultipolar neurons: Each ganglion cell has
many dendrites and asingle axon.
Dendrites receive synapsesfrom the incomingpreganglionic nerve fibers
Axon passes out aspostganglionic fiber.
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Ganglia
Cranio Spinal Autonomic
Cranial nerve ganglia Spinal ganglia Sympathetic Parasympathetic
Cranio Spinal ganglia Autonomic ganglia
ganlionic cells are present as groupsin the ganglion.
Variable size of the ganglion cells
Pseudo unipolar cells
Sensory
No synapse
+++ satellite cells
complete capsule of satellite cells
Evenly distributed
Uniform size Multipolar cells
Secretomotor
++ synapse
+ satellite cells
incomplete capsule of satellite cells
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