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Neurology Chap# 12- Cerebellum & Brainstem

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Cerebellum vital to the control of rapid muscular activities.
ex: speaking, running, typing, dancing.
*does not initiate the movement
MUSCLE SYNERGY - coordination
MOVEMENT RANGE
VELOCITY
STRENGTH
MAINTAINANCE OF BODY EQUILIBRIUM
...
Participates in Motor Learning, Motor Memory, and Movement execution
...
Lesion:
mild weakness, tremor, ataxia, impaired equilibrium
packed gyri
Folia
Divided into cerebellar hemispheres
Midline portion = VERMIS (left & right hemispheres)
Each hemisphere divided in 3 lobes:
Anterior
posterior
Flocculonodular- consists of NODULUs and paired FLOCCULI
Cerebellum connected to Brainstem through 3 peduncles:
Superior
middle
inferior
Both Direct and Indirect projections that ggo to spinals cord, cerebral cortex, and basal ganglia
(Essential for learning skilled movements)
Brainstem
-Connects the Diencephalon to the Spinal Cord
- Control all brain ouptput; cardiac , respiratory,sensorimotor
Midbrain, Pons, Medulla Oblongata
* CRANIAL NERVES 3-12 ORGINATE IN BRAINSTEM!
... brainstem
SUPERIOR Structure from Dorsal view
- the CORPORA QUADRIGEMINA(superior &inferior colliculi)
- the floors of the 4TH ventricle
-and 3 cerebellar penducles.
Brainstem: INTERNALLY consists of ...
Cranial Nerve nuclei,
longitudinal fiber tracts, and the
Reticular formation
RETICULAR FORMATION
Modify, facilitate, and regulate all coritcal functions

Regulate swallowing; CN 5,7,9,10,12

actions such as awaking/sleeping cycle
RF involved with...
Cortical arousal, pain perception, regulate toncil modulation and act of spinal and cranial motor functions.
Responsible for maintaining homestatic state of the brain..
visceral
Brainstem- MIDBRAIN
- Link between the cerebral hemispheres and the peripheral and cranial sensory input systems.

-Contains all incoming sensory & outgoing motor fiber + important reticular and cranial nerve nuclei

-Generate neurotransmitters vital to regualte telencephalic, diencephalic, brainstem and spinal cord functions
Corpora Quadrigemina; 4 rounded elevations (tectum)
-2 Superior Colliculi= reflex control of eye movement, visual reflez and coordination of vestibular generated head & eye move(reflex eye control) searching, tracking

- 2 Inferior Colliculi= Mediate the transmission of auditory impluses from the ear to the thalamus and auditory cortex.
- (auditory transmission)
* 3 subdivisions of the midbrain:
1) tectum- orientation map for survival (roof) lens accomodation
2) tegmentum- contains cranial nerve nuclei, red nucleus, and reticular central gray region (central part)
3) basis pedunculi- consists of pes peduncili
Contain SUBSTANTIA NIGRA
the largest nucleus of the midbrain
-degeneration result in Parkinsons disease
Brainstem- PONS (metencephalic)
separated from midbrain by SUPERIOR PONTINE SULCUS.
and from medulla by INFERIOR PONTINE SULCUS .

- contain all DESCENDING (MOTOR) and ASCENDING (SENSORY) fibers
pons consists on 2 parts:
1) PONTINE TEGMENTUM
2) Basis pontis
attaches the cerebellum to the brainstem
middle cerebellar penduncle
Give rise to Cranial nerves...
CN V, CN VII
Brainstem- MEDULLA OBLONGATA
-houses both sensory + motor fiber tracts down to spinal cord
Major surface structures (4)
VENTRAL MEDIAN SULCUS- divides medulla in half!
PYRAMIDAL TRACT- carries motor info from motor cortex to spinal cord for skeletal muscles.
INFERIOR OLIVARY NUCLEUS-
DORSAL TUBERCULA
After motor fibers cross (from pyramidal tract) the midline, form..
LATERAL CORTICOSPINAL TRACT; a motor pathway of the spinal cord
Internally 2 parts:
1) Tegmentum: contains serval nuclei (vital reflexes)
2) PYRAMID: contains descending motor fibers
3 vital reflex centers + 1:
cardiac center, vasomotor center, respiratory center
(+1) swallowing

* ANY LESIONS CAN BE FATAL