Histology of cerebrum and cerebellum
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Transcript of Histology of cerebrum and cerebellum
HISTOLOGICAL FEATURES OF
CEREBRUM
CEREBELLUM
Prof.J.Anbalagan
CEREBELLUM
CEREBELLUM • Hind brain-
– small brain
• Posterior cranial fosse
• Forms roof of IV ventricle
• Fissures and folia
CEREBELLUM
• Receives sensory data
– Same side spinal cord
– Dorsal and ventral spinocerebellar tract
• Receives Motor data
– from cerebrum opposite side
– Cortico pontine fibers
• Output is motor in function
CEREBELLUM
• Cerebellum – controls the activity of cerebrum and
spinal cord
–dysfunctions • manifested by disturbances in the motor
functions without voluntary paralysis
• Resulted in clumsy, poorly coordinated
loss of skillful movements
CEREBELLUM-Functions
• Responsible for Equilibrium Controls eye and head movements balancing
Postural changes Muscle tone
Smooth execution of voluntary
movements Accuracy Perfection control
White fibers - afferent
• Mossy fibers – Spinal cord
– Vestibular nucleus
– Pons
• Enters through inferior and middle cerebellar peduncle
• Synopses with Purkinje cells through granular cells
White fibers- afferent
• Climbing fibers
– Olivary nucleus
– Accessory olivary nucleus
• Through inferior peduncle
• Enters directly to molecular layer
• Synapses with Purkinje 1:1
White fibers - efferent
• Axons of Purkinje
( except archicerebellum)
• Deep nuclei of cerebellum
• Through superior cerebellar peduncle
Cerebellum-cortex • Pia mater
• Cortex and white fibers
• Cortex-Three layers
• Type of cells
– Stellate cells – Basket cells – Purkinje cells – Granule cells – Golgi type II
• White fibers
– Climbing fibers – Mossy fibers
CEREBELLUM • Layers of cerebellum
• Molecular layer – Dendrite orborization – Densely packed axons run
parallel to surface – Superficially stellate cells – Deeper stellate cells
known as basket cells
• Purkinje layer
• Granular layer – Closely packed granule
cells – Shows clear zones -
glomeruli
CEREBELLUM
PURKINJE NEURON
Stellate cells
Basket cell
CEREBELLUM-GOLGI STAIN
PURKINJEE NEURONS
Cerebellum-dendrite tree
Cerebellum-granular layer-(rosette)
Molecular layer
Granular layer
Purkinje layer
CEREBELLUM MOLECULAR
LAYER
GRANULAR
LAYER
MOLECULAR LAYER
GRANULAR LAYER
PURKINJE LAYER
Cerebrum
• White matter
–Nerve fibers
• Commissural
• Association
• Projection
• Gray matter
–Neurons
–Neuroglia cells
Cerebral cortex- type of neurons
• Six type of neurons • Pyramidal
– Triangular
– Dendrite arises from three angles
– Axon from the base of cell
– Prominent nucleus and Nissl substances
– Small sized pyramidal neuron10-12 micron
– Medium sized neuron 40-50 micron
– Large sized (Betz cells ) > 100 micron
• Stellate/granular cells – Polygonal/triangular
shape
– Dark condensed nucleus
– Dendrites arises all over
– Axon terminate next layer and goes deeper
• Fusiform cells – Oriented perpendicular
to the surface
– One dendrites towards superficially
– One axon towards deeper layer
STELLATE
F
U
S
I
F
O
R
M
• Horizontal cells of Cajal
– Spindle shaped
– Parallel to the surface
– Internuncial type
• Cell of Mortinotti
– Small triangular cells
– Axons goes towards surface
• Golgi type II
– Process ends close to cell body
– Local circuit
CAJAL
MORTINOTTI
GOLGI
Layers of cerebral cortex • Outer Molecular layer
– Horizontal cells + Golgi type II
– Tangential nerve fibers from pyramidal, fusiform and cells of Mortinotti
• Outer granular layer – Small pyramidal cells + stellate
cells
– Dendrites end in first layer
– Axons forms association
• Outer pyramidal layer – Medium and large pyramidal cells
– Axons forms association and commissural fibers
OM
OP
OG
• Inner granular layer – Packed stellate cells – Lot of fibers as band-
Outer band of Baillarger
• Inner pyramidal/ganglion – Large Betz cells – Axons continues as
projection fibers – Horizontal fibers forms
inner band of Baillarger
• Multiform layer/fusiform cells – Spindle shaped cells – Granular, fusiform and
stellate type
Outer band
Inner band
Molecular layer
Outer granular layer
Outer pyramidal layer
Inner granular layer
Inner pyramidal layer
Pleomorphic layer
Pyramidal neuron
Cerebrum-cortex
G