section 6: part 2

Question 1

what is the locus ceruleus important for?

Answer 1

for vigilance & responsiveness to unexpected stimuli

Question 2

what is the “trapezoid body”

Answer 2

it is a region containing the crossing auditory axons and the medial lemnisucs

Question 3

where do the auditory axons terminate?

Answer 3

superior olive

also in the nucleus of trapezoid body, nucleus of lateral lemiscus

Question 4

what do the auditory axons go on to form?

Answer 4

the lateral lemniscus

Question 5

where does the lateral lemnicus terminate?

Answer 5

the inferior colliculus of the midbrain

Question 6

what nuclei controls the muscles of the jaw?

Answer 6

the motor nucleus of 5

Question 7

what does the principal/chief nucleus of 5 do?

Answer 7

processes epicritic sensory information from the face

Question 8

what nuclei receives pain & temp info from the face?

Answer 8

spinal nucleus of 5 in the medulla

Question 9

what nucleus carries proprioceptive info involved in jaw reflexes to the motor nucleus of 5?

Answer 9

the mesencephalic nucleus of 5

Question 10

what does the medial lemniscus carry?

Answer 10

somatosensory info

Question 11

what structures does the medial longitudinal fasciculus interconnect?

Answer 11

innerconnects the superior colliculus, vestibular nuclei, cranial nerve nuclei-3,4,6 and the cervical spinal cord

Question 12

what type of info does the MLF carry?

Answer 12

info coordinating head & eye movements

Question 13

what are the symptoms of destruction to the MLF?

Answer 13

horizontal nystagmus

loss of conjugate horizontal eye movements

Question 14

what two muscles are necessary for horizontal eye gaze? who controls their movements?

Answer 14

lateral rectus of 1 eye and the medial rectus of the over

(nerves 6 and 3) coordinated by the MLF tract

Question 15

is a person still able to do vergence of the two eyes with a pathology in the MLG

Answer 15

yes

Question 16

what structure is referred to as the “horizontal gaze center”?

Answer 16

the paramedian pontine reticular formation (PPRF)

Question 17

what does the PPRF do?

Answer 17

coordinates the horizontal eye movements

Question 18

what is the function of the vestibular nuclei?

Answer 18

receives sensory info about head movements and position from the 8th nerve

Question 19

what are the 3 prominent outputs of the vestibular nuclei?

Answer 19

1. to the cranial nerve nuclei to move eyes via the MLF
2. to the spinal cord via vestibulospinal tracts imp for posture
3. to the cerebellum via the inferior cerebellar puduncle -role in balance & control of reflexive eye movements

Question 20

what are some symptoms of a vestibular nuclei pathology?

Answer 20

nystagmus
loss of balance
vertigo, dizziness, nauseousness

Question 21

what is a positive romberg sign and when is it seen?

Answer 21

loss of balance when the eyes are closed

seen in a vestibular nuclei pathology

Question 22

what muscles does the motor nucleus of 5 innervate?

Answer 22

facial muscles, stapedius, auricularis, stylohyoid muscles & posterior belly of digastric

Question 23

what is the result of a pathology to the facial nucleus?

Answer 23

• paralysis of ipsilateral facial muscles
• mouth droops
• patient unable to close eyes
• loss of parasymp control of lacrimal gland
• loss of corneal reflex
• painful sensitivity to sound (due to loss of strapeidus innervation)

Question 24

what is the function of the abducen’s nuclei?

Answer 24

innervates the lateral rectus muscle of the IPSILATERAL eye

Question 25

what is the symptom of a pathology in the abducen’s nuclei?

Answer 25

paralysis of ipsilateral lateral rectus muscle

eye deviates towards nose (internal strabismus) leading to double vision

Question 26

what does the caudal end of the spinal nucleus of 5 do?

Answer 26

pain & temp info from the face

Question 27

what does the rostral end of the spinal nucleus of 5 do?

Answer 27

epicritic info from the face

Question 28

what is the principal/chief sensory nucleus of 5 do?

Answer 28

epicritic sensation for head & neck

info from SAME side

Question 29

where does epicritic info from the face terminate?

Answer 29

ventral posteriomedial nucleus (VPM) of the thalamus

Question 30

what is the function of the motor nucleus of 5?

Answer 30

innervates muscles of mastication on the SAME side of face

Question 31

what are the symptoms of a pathology of the motor nucleus of 5?

Answer 31

paralysis of the ipsilateral muscles of mastication
weakness in chewing
jaw juts sideways when protruded