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Flashcards in Brainstem; Pons Deck (37):
1

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

2

longitudinal pontine motor fibers; contain?

corticospinal and Corticopontine fibers
also is known as the pyramidal tract

3

unilateral lesion of longitudinal pontine motor fibers (above pyramidal decussation)

contralat motor deficit

4

dorsal portion of the pons

pontine tegmentum
contains ascending and descending tracts
components of several cranial nerves

5

unilateral lesion of medial lemniscus at caudal pons

contralat loss in proprioception and fine touch sensation from body

6

fibers that enter the cerebellum via the SCP

ventral spinocerebellar tract VSCT

7

where do SCP fibers cross?

more rostrally in the caudal midbrain at the decussation of the superior cerebellar peduncles

8

trapezoid body

fibers crossing fr cochlear nuclei to the contralat Sup Olivary Nucleus
sound localization

9

facial colliculus

formed by the facial motor nucleus fibers looping over the abducens nucleus

10

facial motor nucleus

MN innerv skel mm of facial expression
form internal genu that loops over abducens nuc

11

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

12

lesion of facial nucleus only

paralysis of mm of facial expresion
hyperacusis - oversensitivity to sound
loss of blink reflex

13

abducens nerve emerges, and innervates

emerges bet pons and pyramid of medulla
innervates the lateral rectus mm

14

lesion of abducens nerve

medial deviation of ipsilat eye

15

lesion of abducens nucleus

medial deviation of ipsilat eye
inability to adduct contralat eye during horizontal gaze to lesioned side

16

lesion of spinal nucleus and tract of V

ipsilat loss of pain & temp sens from face
loss of blink reflex (afferent limb)

17

superior olivary complex involved in

sound localization

18

paramedian pontine reticular formation (PPRF)

in pontine tegmentum near abducens nuc
imp for coordination of horizontal gaze

19

pontine reticulospinal tract (PRST) main function

facilitate extensor motor neurons

20

lesion of the PPRF

deficits in horizontal gaze

21

transverse pontine fibers major function

cont to motor planning, timing, and coordination of movements

22

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

23

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

24

unilat lesion of the medial lemniscus in the mid pons

contralat loss in prop and fine touch sensation from the body and FACE

25

termination pt of axons in the medial lemniscus carrying info from the body

Ventral Posterior Lateral nucleus (VPL) of the thalamus

26

axons in the medial lemniscus carrying info from the face terminate in the

Ventral Posterior Median nucleus (VPM) of the thalamus

27

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)

28

unilat lesion of the MLF bet the abducens nucleus and oculomotor nucleus

internuclear ophthalmoplegia (impairment of adduction of the affected eye)

29

unilateral lesion of SCP

ipsilateral ataxia (lack of control vol mvmt)
hypotonia
dysmetria (lack of coordination of mvmt)

30

lesion of motor nucleus of V

paralysis and atrophy of the mm of mastication
mandible deviates to affected side

31

mesencephalic nuc of V

primary sensory neurons (pseudounipolar)
innerv masseter mm spindle => afferent limb of the jaw jerk reflex

32

lesion of the mesencephalic nucleus of V

loss of jaw jerk reflex (afferent limb)

33

chief (main) sensory nucleus of V - info

ipsilat epicritic sens from face
via 3 sens br of trigeminal
1st ganglion in the trigeminal ganglia

34

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

35

lesion of chief sensory nuc of V

ipsilat loss of epicritc sens from face

36

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

37

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