bbs ii slide nerve tissue nervous system

2/11/2011

Alya Amila Fitrie , Radita N.A. Ginting
Ginting,, Zulham
Department of Histology
Medical Faculty
University of Sumatera Utara

Nerve Tissue &
Nervous System

Topics
1. Histology of Nerve Tissue
2. Histology of Central nervous System
3. Histology of Peripheral Nervous System
4. Nerve Regeneration

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Cells of Nervous System
Neurons : receptive,
integrative and motor
function of the nervous
system

Neuroglial cells :
supporting &
protecting neurons

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Neurons

Cell body
Ultrastructure of a neuronal cell
body. (From Lentz TL: Cell Fine Structure: An Atlas of Drawings
of Whole-Cell Structure. Philadelphia, WB Saunders, 1971.)


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Main types of neurons
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Special types of neuron

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Neuroglia
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Oligodendrocytes & Schwann cell
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•Schwann Cell :
Produce a myelin sheath
that located around
axons in PNS

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Astrocytes
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Ependymal cells &
Microglia
Ependymal cells : cuboidal or
low columnar epithelial cells,
lining the ventricles of the brain
and central canal of the spinal

cord.
Microglia : small elongated cells
with short irregular processes.

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Central Nervous System
Cerebrum
Cerebellum
Spinal cord

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Cerebrum
Neuron types in the
cerebral cortex:

1. Pyramidal cells
2. Stellate (granul cells)
3. Cells of Martinotti
4. Fusiform cells
5. Horizontal cells of Cajal

Cerebrum (cont..)
Layers
1.Gray Matter / cerebral cortex:
a. Plexiform (molecular)
layer
b. Outer granular layer
c. Pyramidal cell layer
d. Inner granular layer
e. Ganglionic layer
f. Multiform cell layer
2.White matter

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Cerebellum
Function : coordinates muscular
activity and maintain posture
& equilibrium.
Consist of :
1. Gray matter :
• Molecular layer
• Purkinje cell layer
• Granular layer
2. White matter

Cerebellum (cont..)

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Spinal Cord

Consist of :
1. White matter, in the outer
2. Grey matter, has the shape of butterfly

Meninges
Consists of 3 layer :
1. Dura mater : composed of dense
connective tissue, continuous
with the periosteum of the skull.
2. Arachnoid : has 2 component :
• A layer in contact to dura
mater
• A system of trabeculae
3. Pia mater : loose connective
tissue containing many blood
vessels

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Blood-Brain Barrier
BBB, a functional barrier,
prevents the passage of some
substances, from the blood to
the nerve tissue.
Supported by :
1. Occluding junction between

endothelial cells of blood
capillaries of nerve tissue.
2. The expansion of neuroglial cells
processes that envelop the
capillaries.

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Choroid Plexus & Cerebrospinal
Fluid
CP, composed of loose connective tissue of
the piamater, covered by simple cuboidal or
low columnar epithelium.
Function of CP is to elaborate CSF, that fills
ventricles, central canal of spinal cord,
subarachnoid space & perivascular space.
CSF is clear,low density, & very low in protein
content.

Spinal cord
Subarachnoid space

Perivascular space

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Peripheral Nervous System
Nerve fibers
Ganglia
Nerve endings

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Nerve fibers
Consist of axons enveloped by a special sheath
derived from cells of ectodermal origin.
The sheath cell of
PNS→ Schwann cell
CNS → oligodendrocyte

Axon of small diameter → unmyelinated nerve
fibers
Thicker axons → myelinated nerve fibers

Nerve fibers
E : epineurim
P : perineurium
F : fasiculus
V : blood vessels

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Nerve fibers

Nerve fiber

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Nerve fibers
Electron microscope of a
peripheral nerve containing
both myelinated (M) and
unmyelinated (U) nerve
fibers.

Ultrastructural features of
myelinated & unmyelinated nerve
fiber
1. Nucleus & cytoplasm of a Schwann
cell
2. Axon
3. Microtubule
4. Neurofilament
5. Myelin sheath
6. Mesaxon
7. Node of Ranvier
8. Interdigitating processes of Schwann
cells at the node of Ranvier
9. Side view of an unmyelinated axon
10. Basal lamina

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Ganglia
Ganglia are ovoid structures
containing neuronal cell bodies
and glial cells supported by
connective tissue.
They serve as relay stations to
transmit nerve impulses.
There are Sensory ganglia &
Autonomic ganglia.

Sensory Ganglia
Receive afferent impulses that go
to CNS.
Two types :
Cranial ganglia : associated with
cranial nerves.
Spinal ganglia : associated with
the dorsal root of the spinal
nerves.

Large neuronal cell bodies with
prominent fine Nissl bodies
surrounded by abundant small
glial cells called satellite cells.

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Autonomic Ganglia
Appear as bulbous dilatation in
autonomic nerves.
Usually have multipolar neurons.
Have neuronal perikaryons with
fine Nissl bodies.
Enveloped by satellite cells.

Autonomic Nervous System
ANS related to the control of smooth muscle, the
secretion of some glands & modulation of cardiac
rhythm.
ANS are organized & regulated in the CNS.
Anatomically, ANS composed of :
collection of nerve cell located in CNS
fibers that leave the CNS through cranial or spinal nerves.
nerve ganglia situated in the paths of these fibers.

Consist of : Sympathetic & Parasympathetic System

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The Nuclei of ANS
Sympathetic System : collection of nerve cell
bodies (nuclei) located in the thoracic &
lumbar segments of the spinal cord →
thoracolumbar division of ANS
Parasympathetic System : nuclei in the
medulla and midbrain & sacral position of the
spinal cord → craniosacral division of ANS

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Nerve Regeneration
Nerve cell (neuron) :
no regeneration if
soma or dendrites
injured. But, nerve
fiber injured :
regeneration (+)
Neuroglia of CNS,
Schwann cell &
ganglionic satellite
cells of PNS : able
to divide by mitosis
→ regeneration.

Degeneration &
regeneration
of peripheral
nerve

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References
Junqueira, L.C. & Carneiro, J. Basic Histology, Text &
Atlas, 11th edition, Lange Medical Books McGraw-Hill.
2005
Gartner, L.P. & Hiatt, J.L. Colour Textbook of Histology,
Third Edition. 2007
Kierszenbaum AL. Histology & Cell Biology, An
Introduction to Pathology, 2nd ed. Mosby Elsevier. 2007
Pakurar AS, Bigbee JW. Digital Histology, an
interactive CD atlas with review text, Wiley-Liss, 2004
Berman I, Color Atlas of Basic Histology, Second
Edition, Lange, 1998.

THANK YOU…

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