Brainstem, Cerebrum, Cranial nerves Flashcards
what is the brainstem made up of
medulla oblongata, pons and midbrain
what are the general functions of the brainstem
conduit - ascending and descending pathways reach the thalamus and cerebellum from spinal cord - contains relay neurones
integrative - control of CV, respiratory and consciousness in the reticular formation (eg balance)
contains cranial nerves
how many cranial nerves arise from the brainstem
10 out of 12 which form part of the PNS - they contain sensory and motor neurone
rostrally - what is the brainstem continuous with
the diencephalon ie thalamus and hypothalamus
caudally what is the medulla continuous with
with the spinal cord at the level of the foramen magnum
looking at the brainstem ventrally what is present
clivus of occipital bone
looking at the brainstem dorsally what is present
cerebellum
which parts of the ventricular system run through the midbrain
IVth ventricle and cerebral aqueduct
what is the obex
where ventricle IV becomes the central spinal cord
what three structures can be identified in the brainstem rostral to the obex
tectum - only in midbrain (posterior to ventricular system) made up of superior and inferior colliculi
tegmentum - contains cranial nerve nuclei and tracts, reticular formation and some ascend/descend pathway (anterior to ventricles)
basal - most anterior, descending pathways from cerebral cortex
what separates the tegmentum and the basal
substantia negri
ventrally, what can be seen on the medulla
pyramids
olives
postero-lateral sulcus
antero-lateral sulcus
what are the role of the pyramids in the medulla (can be seen ventrally)
in the basal area, bulges of white matter fibres, carry descending motor fibres which cross at the decussation of pyramids
why do we have contralateral control
decussation of pyramids - motor movements controlled by opposite sides of the brain
where would you find the olives of the medulla
lateral to the pyramids
where do you find the postero-lateral sulcus and what nerves arise here
dorsal to olives in the tegmentum areas
cranial nerve IX, X, XI
where do you find the anterolateral sulcus and where arises there
it separates the pyramids and olives in the tegmentum area
cranial nerve XII
the left are right medulla are separated by what
anterior median fissure
what are the two fasiculi which can be seen on the dorsal view
what do they contain
cuneatus = lateral gracilis = medial
ascending sensory information
fasciculi turn into tubercles which are made up of what
afferent nuclei
what does the tegmentum contain vs the basal
T - dorsal contains ascending sensory fibres
B - ventral contains descending motor fibres
what are the three connections of the cerebellum to the rest of the brain
the superior peduncle with the midbrain,
the middle peduncle with the pons,
the inferior peduncle with the medulla oblongata.
where is the obex when the medulla is open and closed
open - rostral to obex
closed - caudal to obex
what is the PMJ
pontomedullary junction which separates the two structures
what is the PmcJ
pontomesencephalic junction - separates the midbrain and the pons
what artery is seen from the ventral pons
basilar artery in the basilar groove
which cranial nerve arises form the PMJ
abducens (VI)
which cranial nerve arises from the ventral pons with a motor and sensory function
trigeminal (V)
what two main structures are seen on the dorsal view of the pons
peduncles
facial colliculus
what is within the ventral view of the midbrain
made up of crus cerebri - ascending and descending fibres
what is within the dorsal aspect o the midbrain
superior and inferior colliculi
what are the inferior and superior colliculi associated with
SC - visual pathway
IC - auditory pathway
what is the reticular formation and what does it do
complex neurones in the tegmentum of brainstem, includes: reticular nuclei - descending motor vital autonomic centres ascending reticular actuating system pain sleep wake arousal
what is the location and role of the cerebellum
cerebellum does fine tune of movement (affects gait)
found under occipital lobe attached to the brainstem by three paired peduncles - superior middle and inferior
what is the flocculonodular lobe
flocculus and nodule in the centre of the cerebellum
how many of the cranial nerves are sensory and motor or mixed
sensory - afferent - 3
motor - efferent - 5
mixed - 4
which nerves are purely sensory
olfactory - 1 (smell)
optic - 2 (vision)
vestibulocochlear - 8 (hearing and balance)
which nerves are purely motor
oculomotor - 3 trochlear - 4 abducens - 6 accessory - 11 hypoglossal - 12
which nerves are both sensory and motor
trigeminal - 5
facial - 7
glossopharyngeal - 9
vagus - 10
what is the function and test of cranial nerve 1-3
olfactory - special sensory smell - smelling item
optic - special sensory - vision - papillary light reflex
oculomotor - somatic motor (extra ocular muscles) visceral motor (colliery muscles) - follow finger test
what is the function and test of cranial nerve 4 and 6
trochlear nerve - somatic motor (superior oblique) - follow finger
abducens - somatic motor (lateral rectus) - follow finger
what is the role of the lateral rectus and what is it innervated by
abducts eye control by abducens
the superior oblique muscle of the eye is controlled by what
trochlear nerve
what is cranial nerve 5 and what are the three divisions with functions and tests
trigeminal
V1 - ophthalmic - somatic sensory (face above eyes) - cotton wool on forehead
V2 - maxillary division - somatic sensory (between eye and mouth) - cotton wool bud on cheek
V3 - madibular division - somatic sensory (lower face and anterior 2/3 tongue)
somatic motor - mastication
cotton wool on jaw and jaw jerk reflex or tense teeth
what is the function and test for cranial nerve 7
facial nerve
somatic motor - muscles of face
special sensory - taste from anterior 2/3 tongue
visceral motor - all glands except parotid
facial movement test
what is the function and test of cranial nerve 8
vestibulocochlear
special sensory - hearing and balance - rinnes and webers test
what is an acoustic neuroma
tumour affecting vestibulocohocelr (8) - hearing loss and tinnitus - loss of balance (can grow to affect facial nerve)
what is the function and test of cranial nerve 9
glossopharyngeal
somatic motor - swallowing
visceral motor - parotid gland
special sensory - taste from posterior 1/3 tongue
somatic sensory - middle ear, pharynx, posterior 1/3 tongue
visceral sensory - carotid body and sinus (monitor O2 and BP)
gag reflex
what is function and test from cranial nerve 10
vagus
somatic motor - pharynx, larynx, uvula
visceral motor/sensory - thoracic and GIT
special sensory - taste of epiglottis and palate
somatic sensory - epiglottis, skin of external ear, larynx
test speaking and uvula movement
what is the function role and test for cranial nerves 11 and 12
11 - accessory - somatic motor - sternocleidomastoid and trapezius - shoulder shrug and rotate head
12 - hypoglossal - somatic motor muscles of tongue
protrude tongue
what is the location and foramen of the first 4 cranial nerves
olfactory - nasal muscosa, olfactory bulb, olfactory tract, extension of telencephalon - foramen - cribifrom plate
optic - retina, optic chisma, optic tract, extensions of diencephalon - foramen - optic canal
oculomotor - PMJ from interpeducnular fossa - foramen - super orbital fissure
trochlear nerve - dorsal midbrain - foramen - superior orbital fissure
what is the location and foramen of cranial nerve 5-7
5 - trigeminal - from the pons - foreman - V1 (superior orbital fissure) V2 (foramen roteundunm) V3 (foramen ovale)
6 - PMJ - foramen - super orbital fissure
7 - cerebellopontine angle - foramen - internal acoustic meatus and out stylomastoid foramen
what are the locations and foramen of cranial nerves 8-10
8 - vestibulocochlear - Cerebellopontine angle - foramen - internal acoustic meatus
9 - glossopharyngeal - lateral to olives on medulla - foramen - jugular foramen
10 - vagus - same as 9
what are the locations and foramen of cranial nerve 11 and 12
11 - accessory - caudal medulla - formen - jugular foramen
12 - hypoglossal - anterolateral sulcus between pyramid and olives - foreman - hypoglossal canal
what are the parasymptateic autonomic ganglia of cranial nerve 3 7 and 9 and which trigeminal branch do they synapse with
3 - ciliary - V1
7 - pterygopalatine - V2
- submandibular - V3
9 - otic - V3
what are the sympathetic autonomic ganglia and trigeminal synapse associated
superior cervical ganglia of the vagus nerve which branch with itself
describe the blood supply to these locations diencephalon brainstem cerebellum spinal cord
D - thalamogeniculate branches and thalamoperforating branches of posterior cerebral artery
B - branches from vertebral and basilar artery
C - same as brainstem
S - two posterior spinal arguers and singular anterior spinal artery
what are the intracranial branches of the facial nerve
greater posterior nerve
nerve to stapedius
chorda tympani
what are the extra cranial branches of the facial nerve
posterior auricular nerve
nerve to digastric and stylohyoid
terminal branches: temporal, zygomatic, buccal, marginal mandibular, cervical
autonomic functions of the cranial nerves are all….
parasympathetic
what is the role of the intracranial greater petrosal nerve
parasympathetic to mucous glands and lacrimal glands via V2
what is the role of the intracranial nerve to the stapedius
motor fibres muscles o the middle ear to suppress hypersensitivity to sound
what is the role of the intracranial nerve chorda tympani
sensory to anterior 2/3 tongue
parasympathetic to submandibular and sublingual glands
what is the difference between upper and lower motor neurone lesions
upper = whole side not usually affected due to combined contra and ipsilateral contribution
lower = whole side affected because all nerves affecting that side are travelling down
