Department of Histology Department of Histology Medical Faculty Medical Faculty University of Sumatera Utara 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
Cells of Nervous System
Neurons : receptive,
integrative and motor
function of the nervous
system
Neurons
Cell body
→ ! "
→
# $ "
→ %
Ultrastructure of a neuronal cell
Main types of neurons
( &
) !
*
*
+ ,
Neuroglia
- (.
-Oligodendrocytes & Schwann cell
/ ,
%0
•Schwann Cell :
Astrocytes
0 1 "
" " " →
" 1
→
Ependymal cells &
Microglia
Ependymal cells : cuboidal or
low columnar epithelial cells,
lining the ventricles of the brain
and central canal of the spinal
cord.
Central Nervous System
Cerebrum
Cerebellum
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
Cerebellum
Function : coordinates muscular activity and maintain posture & equilibrium.
Consist of :
1. Gray matter :
• Molecular layer
• Purkinje cell layer
• Granular layer
2. White matter
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
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.
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
Peripheral Nervous System
Nerve fibers
Ganglia
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
Nerve fibers
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
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.
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.
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
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.
References
Junqueira, L.C. & Carneiro, J. Basic Histology, Text & Atlas, 11thedition, 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, 2nded. 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.
