Histology of Spinal Cord and Cerebellum by Dr. ROOMI

7/31/2019 Histology of Spinal Cord and Cerebellum by Dr. ROOMI

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HISTOLOGY OF NERVOUS TISSUE

BY

DR. MUDASSAR ALI ROOMI (MBBS, M. PHIL)


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SPINAL CORD

It is cylindrical part of CNSwhich runs in vertebralcanal.

It is Covered by 3 layers ofC.T. meninges (dura matter,arachnoid matter, piamatter).

Inner grey matter (H-shaped or butterfly shapedarrangement)

Outer white matter

Two nerve roots- onesensory, one motor.


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SPINAL CORD

In t.s. oval in shape.

More flattened ventrally than dorsally.

Central canal lined by ependymal cells.


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SPINAL CORD

Dorsal median septum

Dorsal median sulcus

Ventral median fissure

Anterior (ventral) horn

Lateral horn

Posterior (dorsal) horn

Dorsal grey commissre

Ventral grey commissure

Dorsal white column

Lateral white column Ventral white column

Dorsal root of spinal nerve

Ventral root of spinal nerve

Dorsal root ganglion


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Anterior horn of spinal cord

Anterior horn of spinal cord has got multipolar

neurons.

Important cells in ant. Horn- @ motor neurons

Functionally these are motor neurons.


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HOW TO DRAW IT!


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Identification points of spinal cord

1. Central canal is presentlined by ependymal cells

2. Inner butterfly shaped

arrangement of greymatter

3. Large Multipolarneurons in the anterior

horn4. Outer white matter

5. Pia matter on thesurface.


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CEREBELLUM Two cerebellar hemispheres

Surface shows fissures whichdivide the cerebellum into

lobules

Grey matter on the surface

Inner white matter

Deep nuclei of grey matter also

present in the white matter


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CEREBELLUM

3 layers of cerebellar

cortex:

1. Molecular layer

2. Purkinje cells layer

3. Granular layer


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1. Molecular layer

Cell population is low

Mainly composed of cell

processes

Stellate cells and basketcells are present here.


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1. Molecular layer (cont.)

Stellate cells:

Have small star shaped cellbodies

Each cell has many short thindendrites

a fine unmyelinated axon ispresent which make synapseswith the dendrites of the purkinjecells

Basket cells:

Also have a small cell body

Numerous branching dendrites

Unmyelinated axon gives offdescending branches which formbasket-like arborizations aroundthe bodies of the Purkinje cells


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Single row of Purkinje

cells are present here


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2. Purkinje cells layer (cont.)

Purkinje cells:

these are large,

multipolar neurons.

Vesicular nucleus with aprominent nucleolus

Large number of Nissl

granules in thecytoplasm


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cerebellum


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Fan shaped, repeatedlybranching dendriticarborization which entersthe molecular layer

Axon arises from thebase, passes through thegranular layer to enterthe underlying whitematter

Most of the axons of thePurkinje cells terminate inthe deep cerebellarnuclei.


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3. Granular layer

This layer contains densepopulation of small neuronscalled granule cells

Granule cells appear asclosely pecked nuclei which

stain deeply basophilic Golgi type II cells are also

present in the granularlayer.

Glomeruli: these are

irregularly scattered lighterstaining areas within thegranular layer.


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3. Granular layer (cont.)

Each granule cell gives 4-5short dendrites

The unmyelinated axon ofthe granule cells ascends tothe molecular layer where it

bifurcates into twobranches which run parallelto the surface of the cortexand are called as parallelfibers.

Golgi type II cells have shortaxon which make synapsewith the terminal branhchesof the Mossy fibers.


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Afferent fibers of the cerebellum

Climbing fibers:

these fibers originate in theinferior olivary nucleus ofmedulla oblongata.

These fibers synapse with

the dendrites of the Purkinjefibers in the molecular layer.

Mossy fibers:

these fibers originate in thespinal cord and in brain stem.

They make contact with thedendrites of the granules cellsand axons of the Golgi type IIneurons.

CLIMBING FIBERS


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cerebellum


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HOW TO DRAW IT!


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Cerebellum- Identification points

Outer grey matter

having 3 layers

(molecular layer,

Purkinje cell layer,granular layer)

Inner white matter

Histology of Spinal Cord and Cerebellum by Dr. ROOMI

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