Section 6 Notes Flashcards
axons from the base of the pons go to the cerebellum via the
middle cerebellar peduncle
cranial nerves evident on the surface of the basis of the pons are
5, 6, 7, 8
CN ___ pierces the middle cerebellar peduncle
trigeminal
what does the superior cerebellar peduncle carry?
axons from the cerebellum to the
- brainstem
- forebrain
landmarks on the dorsal surface of the pons (floor of the 4th ventricle)
- vestibular areas
- facial colliculus (abduscens is below as well as the facial nucl;eus)
landmarks of the transition to the medulla to the pons
- pryamids disasppear
- striated appearence of the basis of the pons (pyramidal tract still embedded here)
dorsally
- vestibular nuclei
- blending of the inferior cerebellar peduncle with white matter of the cerebelum
the corticospinal axons form part of the ___ in the midbrain
crus cerebri
what does the middle cerebellar receiveinput from
primarily the pontine nuclei, which receive input from the cerebral cortex
the axons of the superior cerebellar peduncle arise from the
deep cerebellar nuceli
_____ comprises much of the gore gray matter of the tegmentum
pontine reticular formation
pontine reticular formation controls functions like
eye movements, sleep, arousal
desribe the relationship to the absudcens and facial nuceli in the pons.
facial ncuelsu is more rostral and lateral but loops caudally around the abduscens forming the genu of the facial nerve (causes the bump or the facial colliculus)
function of the reticular formaiton in the pons near trigeminal motor n.
invovled with chewing responses
function of the reticular formaiton in the pons near facial nucleus
invovled with lip movements and facial expression
function of the reticular formaiton in the pons near abduscens nculei
invovled in coordinating eye movement
The raphe nuclei of the pons (serotonergic) project rostrally throughout the forebrain and modulate responses of___ and ___
hypothalamic and cerebral neurons.
noradrenergic neurons within the pons send projections to the spinal cord and are involved in___ and ___
autonomic reflexes and pain sensation.
where is the locus cereuleus located?
rostral pons and caudal midbrain
___ contains melanin granules
locus cerulues
what is the importance of locus ceruleus?
produce norepeinphrine
important for vigilance
important for responsive ness to unexpected stimuli in the environment
projections from the locus ceruelus
to:
- spinal cord
- cerebral cortex
- cerebelar cortex
Approximately half of the second order neurons of cochlear nuclei
send axons across the midline, through the region containing the ____
medial lemniscus
what is the trapezoidal body?
contains crossing auditory axons and the medial lemniscus
auditory axons from the cochlear nuclei, no matter if they cross or not, synapse in the
supeiror olive and other auditory nuclei
what does each lateral lemniscus carry?
auditory signals from both ears
function of motor nucleus of cn 5?
what does X cause?
control the muscles of the jaw
X causes atrophy of ipsilateral jaw muscles. jaw deviates to the same side of the lesion
Principa Sensory Nucleus of CN 5 function
processes epicritc from the face
(unlike the spinal trigem in medulla which gets pain and temp)
input of the mtoor nculeus of 5
mesencephalic tract of CN 5 carries proprioceptive info from the mesenepahlic nulceus of 5 in the pons
e mesenepahlic nulceus of 5 sends information to the cerebellum via the
reticular formation
medial lemniscus tract terminates in the
vpl
ALS terminates in the
- some in the reticular formaiton
- some in the periaqueductal gray
- vpl and intralaminar nuclei and others
pyramidal tract leaves the cortex via the
posterior limb of the internal capsule
where do corticobulbar axons cross?
cross right at their target nuclei (not at the decussations)
sx of MLF X
a horizontal nystagmus or a loss of conjugate horizontal eye movements
paramedian pontine reticular formation is located in the
reticular formaiton of the pons
paramedian pontine reticular formation is involved in
conjugate horizontal eye movements
3 output of the vestibular nuclei
- CN that move eyes: 3,4,6
- spinal cord – vestibulospinal tracts (maintain posture)
- cerebellum – via the inferior cerebellar peduncle
ROmberg’s sign
what is it
what causes it
loss of balance more proncounced when patients eyes are closed
seen with vestibular nuclei damage in the pons
what is innervated by the facial nucleus in the pons
the facial muscles, the stapedius, auricularis, and stylohyoid muscles and the posterior belly of the digastric.
X facial nucelus in the pons
- paralysis of ipsilateral facial muscles
- drying of cornea due to loss of parasymps of lacrimal
- loss of corneal reflex
- painful sensitivity to sound due to weakness of stapedius
lesions to corticobulbar axons projecting to the facial nucleus
contralateral facial paralysis below the forehead
describe the spinal nucleus and tract in the medulla vs pons
in the medulla: pain and temp from face on same side
pons: carry epicritic from the face
function of the princeipal nucleus of cn 5
epicritic of head and neck
epicritc sensation from head and neck
pathway from the CN 5 entering the pons
synapses in the principal sensory nucelus of cn 5
travels cross midline
trigeminothalamic axons travel to medial lemniscus
termiantes in the VPM
principal sensory nucelus of cn 5
X symptoms
loss of vibration, position sense, and reduced sens eof touch on the ispialteral side of face
X of motor ncuelus fo CN 5
- jaw juts sideways when protruded
- paraylsis of ipsilateral muscles of masticaiton
inferioer cerebellum carries info from the
spinal cord and medulla
pontine neurons relay information to the ____ middle cerebellar peduncle
contralaterla
____ is the main outflow of the cerebellum
superior cerebellar peduncle
axons from the superior cerbellar peduncle arise from the ___
deep cerebelllar ncueli
axons from the superior cerbellar peduncle arise (from the deep cerebellar nuclei) then go to the
tegmentum of the pons
then most ross in the decussation of the superior peducnles
targets of the axons from the superior cerbellar peduncle
after crossing in the decussation of the superio cerbellar peduncel?
- reticular formation
- red nculeus (midbrain)
- ventral anterior and ventral lateral nuclei
input of the deep crebellar nuclei
mostly form the cortex
output of the deep cerebellar ncueli
brainstem
medial deep crebellar ncueli
fastigial and globose
lateral deep cerebellar ncueli
emboliform and dentate
____ deep cerebellar receive a bulk of connectiosn from AXIAL RELATED STRUCTURES
medial (fastigial and globose)
____ deep cerebellar receive a bulk of connectiosn from APPENDICULAR RELATED CONTROL
EMBOLLIFORM AND DENTATE
midline parts of the cerebellum include the
vermis and flocculus
lateral pathology of the cerebeluum is located in the
hesmipheres
The cerebellum has no direct connections to cranial nerve nuclei or the spinal cord.
the right cerebellar projections are to the vestibular nuclei which affect the ____ side of the body
right
- cerebellar information about the right side of the body is sent to the left red nucleus and left VA and VL nuclei in the thalamus. The left red nucleus is the origin of the rubrospinal tract, which crosses *
what nuclei are in the pons
cranial nerves –
- abduscnes
- facial nuclei
- motor part of trigem
- principal sensory of trigem
- vestibular nulcei.
- spinal nucleus of trigem (carry epicritc)
other –
- pontine reticular formation nuclei
- superior olivary n.
what major tracts run through the pons?
- medial lemniscus - carry epicritic from opposite side of the body (crosses in medulla)
- ALS
- pyramidal tracts
- corticobulbar and cortciopontine tracts - to ponhtine nuclei or other nuclei
- MLF
