Week 9 Quiz

Question 1

what are the main motor/sensory functions of each cranial nerve?

Answer 1

CN I, olfactory: smell
CN II, optic: sight
CN III, oculomotor: eye movement, pupil and lens function
CN IV, trochlear: eye movement
CN V, trigeminal: facial sensation and chewing
CN VI, abduncens: eye movement
CN VII, facial: taste and facial expression
CN VIII, vestibulo-cochlear: hearing equilibrium
CN IX, glossopharyngeal: taste and swallowing
CN X, vagus: thoracic and abdominal viscera and speech, swallowing and abdominal viscera
CN XI, accessory: head and shoulder movement
CN XII, hypoglossal: tongue movement

Question 2

which cranial nerves are sensory, motor, or both?

Answer 2

CN I Olfactory: Some
CN II Optic: Say
CN III Oculomotor: Marry
CN IV Trochlear: Money
CN V Trigeminal: But
CN VI Abducens: My
CN VII Facial: Brother
CN VIII Vestibulocochlear: Says
CN IX Glossopharyngeal: Bigger
CN X Vagus: Brains
CN XI Spinal Accessory: Matter
CN XII Hypoglossal: Most

Question 3

where are somatic/visceral and sensory/motor regions located on the spinal cord?

Answer 3

somatic sensory: lie at the very top of the central canal, most lateral once the fourth ventricle splits
visceral sensory: lie right above the sulcus limitans, medial to the somatic sensory once the fourth ventricle splits
visceral motor: lies right below the sulcus limitans, lateral to the somatic motor once the fourth ventricle splits
somatic motor: lies at the very bottom of the central canal, most medial once the fourth ventricle splits
(diagram on L11S4)

Question 4

where are the two additional somatic/visceral and sensory/motor regions located on the brainstem?

Answer 4

branchial motor: between visceral motor and somatic motor in medial section
special sensory: lateral to somatic sensory in lateral section
(diagram on L11S4)

Question 5

where are the oculomotor, trochlear, abducens, and hypoglossal nuclei and what muscles do they innervate?

Answer 5

oculomotor: lies below the inferior colliculi on the posterior side of the brain stem, line the bottom triangle of the PAG, innervates the superior, inferior, and medial recti and inferior oblique
trochlear: lies right below the oculomotor nuclei on the posterior side of the brain stem, lie just below the outer rim of the PAG, innervates the superior oblique
abducens: lies between the cerebellar peduncles, innervates the lateral rectus
hypoglossal: lies along the pyramids below the fourth ventricle, innervates the tongue muscles

Question 6

what do the different nuclei of the trigeminal nerve convey?

Answer 6

mesencephalic nucleus: conveys proprioception and touch
spinal trigeminal nucleus: mediates pain and temperature

Question 7

what are the three segments of the trigeminal nerve?

Answer 7

opthalamic: innervates the forehead area
maxillary: innervates the upper cheek and mouth
mandibular: innervates the lower jaw

Question 8

what are the major connections of the trigeminal nerve?

Answer 8

1. mesencephalic fibers that innervate muscle spindles and get sensory information from mandibular division, responsible for jaw jerk reflex, 2. tactile afferents
2. motor efferents (masseter muscle)
3. pain/temperature efferents

Question 9

what do the four segments of the facial nerve do?

Answer 9

somatic sensory: outer ear
visceral sensory: taste buds
brachial motor: facial muscles
autonomic: salivary and lacrimal glands

Question 10

how does upper motor neuron damage affect facial regions differently?

Answer 10

uppper facial muscles get bilateral innervation by CN VII, but lower face only gets contralateral innervation by CN VII nuclei in the brainstem before they combine in the cortex, if the lesion is in the cortex then you will see lower facial paralysis

Question 11

what is medial medullary syndrome?

Answer 11

damage in the brainstem to the hypoglossal nerve affects that side of the cortex but the contralateral side of the body since pyramidal tract crosses and damage occurs before cross, this means tongue will move towards side of lesion since muscle on that side is paralyzed