Cerebellum Flashcards
بسم الله الرحمن الرحيم وبه نستعين
Vestibuloscerebellum is ?
Floculonodular lobe + Part of vermis
for balance and equillibrium
called archi cerebellum
Spinocerebellum is ?
Paleo cerebelleum
Vermis and intermdeiate zone
For coordination of movments + muscle tone + skilled movments
Cerebrocerebellum is ?
Lateral part of cerebellar hemishperes
it is called neocerebellum
and is for ?
pANINING ANd programming of movements
some characteristics of cerebellum
-No snesory loss ( unconsiuos propricoetpstion is not sensed )
-No paralysis as no direct connection to spinal cord
-Ipisilateral muscle control
Connection to Contralateral motor cortex
-Damp + promote motor activity
Structure of cerebeullum
Cerebellar cortex + deep nuclei
Cerebellar cortex :-
Purkinje
Gogli
Garrnule
basket
stellate
__________________
deep nuclei
Fastigial medial
Dentatae lateral
INterpositous
Connections of cerebeullum
Cerebellar cortex + deep nuclei
Cerebellar cortex :-
Purkinje
Gogli
Garrnule
basket
stellate
__________________
deep nuclei
Fastigial medial
Dentatae lateral
INterpositous
afferents enter both the cortex and the deep nuclei
but efferents only Radiatates from deeeep Nucel i
Cerebellar afferents mentio n
=Climbing fibers from the Inferior olivary nuceleus.
Mossy fibers :-
PVRS
Pontine nuclei
vestibular nucceli
reticular formation
Spinal cord
________________
deep cerebellar nuclei afferents
Stimulatory from climbing and mossy pontine vestibular reticular spinal
inhibitory from purkinje cells
The net effect is excitatory to deep nuclei
Turn on /turn off cerebellar out put explain
When doing rapid movements the Cerebellum deep nuceli is in turn on state giving activation to cortex to activate motor neurons to perform movements
after few milliseconds there is inhibition by purkinje cels to Deep nuclei to stop cortex stimulation and stop performance of movments
_________________
Damping of movmnets
pervents overshooting and Oscillitations
_____________________
there is no reverbating circuits
the effect of cerebellum is tranisent whhhhhy/?
due to no Reverbrating cirucits
Explain climbing fibers Cerebellar circuit
From inferior olivary nucleus
the climing fibers stimulates by aspartae :
deep nuclei form movemet performance
Purkinje cells for inhibition of movments to do a new movment
SO it works by discharge to deep nuclei form perforamnce and strong low frequency stimulation of Purkinje cells for Inhibition of movements so uesd in ?
MOTOR Learning (training) cognitive functions
after learning the movemnts the discharge of climbing fibers for this movements slow down
Mossy fibers cerebellar circuit explain …
From PVRS
Pontine vestiubolo Reticular and spinal cord
and it is excitatory by glutamate !
To deep nuclei
and Gragnule cells 500 CELL giving parallel fibers for Purkinje cells basket stellate golgi cells
For Modulatio and Release of Motor programs
For modulation and relasing programs ?
For training and motor learning coginitve functions
الاولي
mossy
الثانية
climbing
Describe funtions of cerebellum
Vestiblocerebellum for Balance and equlibrium and position how ?
Receiveing From Vestibular recpetors and Proproceptive impulses !
from head and body movements:
1-sends to medial longitudinal bundle to Adjust eye movemnt with head movements as it Sends to cranial nerves 346
2-Measuring and computing sites of body parts and expect theri sites at next movement and achicve balance between agonists and anatagonists
through Vestibulospinal and reticulospinal that contorl axial and proximal limb muscles movements
lESION CAUSES? truncal ataxia how=
Drunken gait+nystagmus
_______________________________________
Voluntary movements
Spinocerebellum receving spinal Proprioception impulses and motor cortex plan
1-Servocomparator : compare the plan with the actual movements and detects any error then sends to area 4 or Red nucleus to send corrective impulses then after the end of movemnt inhibits cortex extarpyramidal tracts casuing braking
2-Regulation of Ballistaic movements : by mossy fibers controlling turn on duration and turn of these preplanned movements
3-Damping: balance agonist with antagonist to stop movements at proper time by sending subconscous impulses by vestivular and reticlospinal tracts of axial and proimal limb muscles
lesions : dysmertia + over or under shooting +Tremors
________________________________________
Neocerebellum cerebrocerebellum
1-Planning of movments with premotor and supplemental motor area and it plans the next movement during the excution of first movments to do smooth movements
2-Prediciting and timing : Receiving sensory impulses and evaluate the situaton needing sutiable range speed rate of movements casuing adjustment of movements to reach goal
3-Extromotor predicting : by visual and auditory impulses reaching cerebellum expecting events to occur
________________________________
Control of stretch reflex and muscle tone
Spinocerebellum +++
Describe funtions of cerebellum
Vestiblocerebellum for Balance and equlibrium and position how ?
Receiveing From Vestibular recpetors and Proproceptive impulses !
from head and body movements:
1-sends to medial longitudinal bundle to Adjust eye movemnt with head movements as it Sends to cranial nerves 346
2-Measuring and computing sites of body parts and expect theri sites at next movement and achicve balance between agonists and anatagonists
through Vestibulospinal and reticulospinal that contorl axial and proximal limb muscles movements
lESION CAUSES? truncal ataxia how=
Drunken gait+nystagmus
_______________________________________
Voluntary movements
Spinocerebellum receving spinal Proprioception impulses and motor cortex plan
1-Servocomparator : compare the plan with the actual movements and detects any error then sends to area 4 or Red nucleus to send corrective impulses then after the end of movemnt inhibits cortex extarpyramidal tracts casuing braking
2-Regulation of Ballistaic movements : by mossy fibers controlling turn on duration and turn of these preplanned movements
3-Damping: balance agonist with antagonist to stop movements at proper time by sending subconscous impulses by vestivular and reticlospinal tracts of axial and proimal limb muscles
lesions : dysmertia + over or under shooting +Tremors
________________________________________
Neocerebellum cerebrocerebellum
1-Planning of movments with premotor and supplemental motor area and it plans the next movement during the excution of first movments to do smooth movements
2-Prediciting and timing : Receiving sensory impulses and evaluate the situaton needing sutiable range speed rate of movements casuing adjustment of movements to reach goal
3-Extromotor predicting : by visual and auditory impulses reaching cerebellum expecting events to occur
________________________________
Control of stretch reflex and muscle tone
NEO+++PAELO —- NET ++++
