Section 5, Part 3

Question 1

What terminates in the gracile nucleus?

Answer 1

Dorsal column axons of the gracile fasciculus

Question 2

What are arcuate fibers?

Answer 2

They are axons of the gracile and cuneate nuclei neurons that cross the midline and carry somatosensory and proprioceptive information from the upper and lower half of the body

Question 3

Do arcuate fibers cross to the opposite side?

Answer 3

Yes they decussate

Question 4

After arcuate fibers cross the midline, what are they renamed?

Answer 4

Medial Lemniscus

Question 5

Do fibers ascend the medial lemniscus in a somatotopic fashion?

Answer 5

Yes they do

Question 6

If you were to lesion the medial lemniscus…what would the symptoms be?

Answer 6

Epicritic deficits on the opposite side of the body

Question 7

WHen does somatosensory information from the face join the medial lemniscus?

Answer 7

The pons

Question 8

If you were to lesion the anterolateral tract in the medulla….what would the symptoms be?

Answer 8

loss of pain and temperature on the opposite side of teh body

Question 9

When the anterolateral tract in the medulla is lesioned, what other structure is usually affected as well?

Answer 9

Spinal tract of nucleus V….so you get pain and temp loos on the same side of the head

AND

Vestibular area/ inferior cerebellar peduncle…so there are sometimes cerebellar and vestibular symptoms

Question 10

what is the function of the inferior cerebellar peduncle?

Answer 10

Major cerebellar related pathway in the medulla that carries mainly afferent information to the cerebellum from several locations

Question 11

What is the accessory cuneate nucleus?

Answer 11

A pateral protrusion of the cuneate nucleus that receives cuneate fasciculus axons carrying proprioceptive information from the upper half of the body

Question 12

Where can the inferior olivary nucleus/ complex be found?

Answer 12

The ventrolateral portion of the open medulla and the rostral part of the closed medulla

Question 13

What is the function of the inferior olivary nucleus?

Answer 13

It is a cerebellar relay

Question 14

Where does the input of the inferior olivary nucleus come from?

Answer 14

The red nucleus, spinal cord and cerebral cortex

Question 15

Where does the inferior olivary nucleus send axons to?

Answer 15

It sends axons to the inferior cerebellar peduncle

Question 16

What are the symptoms of an inferior cerebellar peduncle lesion?

Answer 16

ataxia and intention tremor on the ipsilateral side of the body

Ex- patients lean to the side of the lesion and have clumsiness and a tremor when using the ipsilateral hand

Question 17

What artery supplies the inferior cerebellar peduncle?

Answer 17

PICA

Question 18

Where do the fibers of CN XII emerge from on the brainstem?

Answer 18

exit between the olive and the pyramid

Question 19

If you were to lesion the left CN XII, what side would the tongue deviate to?

Answer 19

It would deviate to the left (damage is ipsilateral) i the lesion is to the nerve or the nucleus

If the lesion is in the cortex or anywhere rostral to the medulla it would deviate to the right (conralateral)

Question 20

What is the nucleus ambiguous?

Answer 20

A long thin column of motor neurons that occur at most levels of the medulla

Question 21

What do the axons of the nucleus ambiguous control?

Answer 21

They mainly project CN 9 and CN 10 to innervate the larynx and the pharynx

Question 22

If there is a (unilateral) lesion to the nucleus ambiguous, what are the symptoms?

Answer 22

Hoarsness, impaired swallowing and asymmetry of the soft palate

Question 23

What is the dorsal nucleus of the vagus made of?

Answer 23

Preganglionic parasympathetic neurons of teh vagus nerve

They terminate in the ganglia related to cardiac muscle and smooth muscle

Question 24

What does the solitary nucleus recieve?

Answer 24

It receives afferent information from the pharynx and larynx and from the cardiovascular system and the GI system via cranial nerves 7, 9 and 10

Question 25

What is the vestibular area?

Answer 25

It is an area that recieves vestibular information from CN 8 and has different projections to other nuclei for vestibular reflexes and to the cerebellum via the inferior cerebellar peduncle

Question 26

Where are the dorsal and ventral cochlear nuclei found?

Answer 26

At the transition between the pons and medulla on the external surface of the inferior cerebellar peduncle

Question 27

What is the function of the cochlear nuclei?

Answer 27

They recieve primary afferent input from the auditory portion of the CN 8 (the origin of the auditory pathway

Question 28

If there is damage to the left cochlear nuclei….what symptoms are found?

Answer 28

Deafness of the ipsilateral ear

Question 29

Damage to the vestibular nuclei results in what symptoms?

Answer 29

Nystagmus, vertigo ad problems with balance

Question 30

What are the symptoms of a CN VIII lesion?

Answer 30

Deafness in ipsilateral ear, nystagmus, vertigo, problems with balance

Question 31

What are the symptoms of a CN IX lesion?

Answer 31

Loss of gag reflex on the side of the oropharynx of the nerve injury (afferent loss to the solitary nucleus)

Question 32

What are the symptoms of a CN X lesion?

Answer 32

Hoarseness due to loss of control of the larynx and difficulty swallowing, asymmetry of the soft palate

bilateral involvement can lead to chocking

Question 33

What are the symptoms of a CN XI lesion?

Answer 33

inability to elevate the ipsilateral shoulder, difficulty to turn and tilt head, fasciculations and atrophy of the sternocleidomastoid and trapezius muscles

Question 34

What are the symptoms of a CN XII lesion?

Answer 34

Paralysis of the ipsilateral tongue muscles, deviation towards the side of the weakness upon protrusion, atrophy, fasciculations of tongue muscles ipsilaterally