Brainstem; Pons Flashcards
pontine fibers; origin, path, termination
originate in pontine nucleus cross the midline form midd cerebellar peduncle terminate in the cerebellum Role: relay info fr the cerbral cortex to the cerebellum
longitudinal pontine motor fibers; contain?
corticospinal and Corticopontine fibers
also is known as the pyramidal tract
unilateral lesion of longitudinal pontine motor fibers (above pyramidal decussation)
contralat motor deficit
dorsal portion of the pons
pontine tegmentum
contains ascending and descending tracts
components of several cranial nerves
unilateral lesion of medial lemniscus at caudal pons
contralat loss in proprioception and fine touch sensation from body
fibers that enter the cerebellum via the SCP
ventral spinocerebellar tract VSCT
where do SCP fibers cross?
more rostrally in the caudal midbrain at the decussation of the superior cerebellar peduncles
trapezoid body
fibers crossing fr cochlear nuclei to the contralat Sup Olivary Nucleus
sound localization
facial colliculus
formed by the facial motor nucleus fibers looping over the abducens nucleus
facial motor nucleus
MN innerv skel mm of facial expression
form internal genu that loops over abducens nuc
lesion of facial nerve
paralysis of mm of facial exp hyperacusis - over sensitivity to sound *loss of lacrimation & salivation *loss of taste in ant 2/3 of tongue loss of blink reflex (motor limb) *means nerve lesion not just nuclei
lesion of facial nucleus only
paralysis of mm of facial expresion
hyperacusis - oversensitivity to sound
loss of blink reflex
abducens nerve emerges, and innervates
emerges bet pons and pyramid of medulla
innervates the lateral rectus mm
lesion of abducens nerve
medial deviation of ipsilat eye
lesion of abducens nucleus
medial deviation of ipsilat eye
inability to adduct contralat eye during horizontal gaze to lesioned side
lesion of spinal nucleus and tract of V
ipsilat loss of pain & temp sens from face
loss of blink reflex (afferent limb)
superior olivary complex involved in
sound localization
paramedian pontine reticular formation (PPRF)
in pontine tegmentum near abducens nuc
imp for coordination of horizontal gaze
pontine reticulospinal tract (PRST) main function
facilitate extensor motor neurons
lesion of the PPRF
deficits in horizontal gaze
transverse pontine fibers major function
cont to motor planning, timing, and coordination of movements
route of transverse pontine fibers
origin pontine nuclei, cross the midline, form Midd cerebellar peduncle, terminate in the cerebellum
relay info from cerebral cotex to cerebellum
unilat lesion of descending longitudinal pontine motor fibers in the mid pons
contralat motor deficit in body
contralat drooping of the corner of the mouth
unilat lesion of the medial lemniscus in the mid pons
contralat loss in prop and fine touch sensation from the body and FACE
termination pt of axons in the medial lemniscus carrying info from the body
Ventral Posterior Lateral nucleus (VPL) of the thalamus
axons in the medial lemniscus carrying info from the face terminate in the
Ventral Posterior Median nucleus (VPM) of the thalamus
the ascending medial longitudinal fasciculus (MLF) connects the vestibular nuclei with the nuclei of the….
abducens
trochlear
oculomotor nerves;
circuitry for the vestibulo-ocular reflex (VOR)
unilat lesion of the MLF bet the abducens nucleus and oculomotor nucleus
internuclear ophthalmoplegia (impairment of adduction of the affected eye)
unilateral lesion of SCP
ipsilateral ataxia (lack of control vol mvmt)
hypotonia
dysmetria (lack of coordination of mvmt)
lesion of motor nucleus of V
paralysis and atrophy of the mm of mastication
mandible deviates to affected side
mesencephalic nuc of V
primary sensory neurons (pseudounipolar)
innerv masseter mm spindle => afferent limb of the jaw jerk reflex
lesion of the mesencephalic nucleus of V
loss of jaw jerk reflex (afferent limb)
chief (main) sensory nucleus of V - info
ipsilat epicritic sens from face
via 3 sens br of trigeminal
1st ganglion in the trigeminal ganglia
path of epicritic info from face
3 sens br of trig -> trig ganglia -> chief sens nuc of V - decussates -> medial lemniscus -> ascends to VPM thalamus (3rd neuron) -> somatosensory cortex
lesion of chief sensory nuc of V
ipsilat loss of epicritc sens from face
lesion of trigeminal nerve
loss of blink reflex (sensory limb)
ipsi loss of gen sensation (epi&proto) from face and scalp
jaw deviation toward lesion
pontine reticulospinal tract (PRST), origin, termination, function
originates in nuc reticularis pontis caudalis oralis in pontine reticular formation
terminates; spinal cord
function; fac ext MN
