CN 8,9,10,11,12

Question 1

CN 8 splits into two nerves that have what function

Answer 1

Cochlear: hearing
Vesicular: equilibrium

Question 2

CN8 pathway: sounds waves go in the EAM to the TM and are amplified by ossicles the vibration then reach the _____ _____ and are transmitted along the _______

Answer 2

Oval window

Cochlea

Question 3

Vibrations are transmitted along the cochlea and its ____ ____ form ______ ____ with primary sensory neurons that have cell bodies in the ______ ganglion

Answer 3

Hair cells form excitatory synapses

Cells bodies in the spiral ganglion

Question 4

From the spiral ganglion in the cochlea axons are sent to the _____ nerve that synapses with _____ and ______ ______ nuclei. Hearing ascends ______ through ______ to reach the _____ ____ then _____ _____nuclei then _____ ______

Answer 4

Cochlear
Dorsal and ventral cochlear nuclei
BILATERALLY through BS
Reach inferior colliculi

Medial geniculate nuclei
Auditory cortex

Question 5

Organ of corti

Answer 5

Aka inner ear

Hair cells of cochlea and supporting cells

Receives auditory signals and conveys info via cochlear portion of CN8

Question 6

Lesions distal to the nuclei / in BS of CN 8 causes what?

Answer 6

Nothing. Cochlear nuclei ascend bilaterally so other side compensates

Question 7

Vestibular pathway of CN8. Semicircular canals detect ________ _____ and utricle/saccule detect ____ ____ both which activate _____ ____ that activate ____ _____ neurons which have cell bodies in ____ ______

Answer 7

Angular acceleration
Linear acceleration

Activate hair cells

Bipolar sensory neurons

Vestibular ganglia

Question 8

Bipolar sensory neurons with cell bodies in vestibular ganglia send axons to ____ ____ that convey information to ___ _____nuclei in the ____ ____. ______ connects nuclei involved in eye movements to each other and to the ____ nuclei which mediates ______ _______. Ascending pathways from vestibular nuclei replay in _____ nucleus of the thalamus to reach the ____ ____

Answer 8

Vestibular nerve
4 vestibular nuclei in BS
MLF 
Vestibular nuclei
Mediates vestibuli-ocular reflex
VPM
Cerebral cortex

Question 9

Rotation of the head is detected by?

Answer 9

Semicircular canals

Question 10

Linear acceleration of the head is detected by what?

Answer 10

Otoliths in utricle and saccule

Question 11

MLF connects nuclei involved in eye movements to each other and mediates what reflex?

Answer 11

Vestibulo-ocular reflex

Question 12

Oscillipsia

Answer 12

Images in the visual field seem to oscillate or jump when they’re actually still to do vestibular mechanism dysfunction

Question 13

What may cause unilateral hearing loss

Answer 13

Disorders of

Ext. auditory canal
Middle ear
Cochlea
CN8
Cochlear nuclei

Question 14

Can lesions in CNS proximal to choclear nuclei cause unilateral hearing loss?

Answer 14

No

Question 15

Conductive hearing loss

Answer 15

Something obstructing ear

Ex; otitis media, membrane perforation, sclerosis of middle ear ossicles

Question 16

Sensorineural hearing loss

Answer 16

Disorders of the cochlea
Meningitis
Ototoxic drugs
Head trauma
Viral infections
Again
Meniere’s disease
Cerebellopontine angle tumor 
Internal auditoryinfarct

Question 17

What can vertigo be caused from

Answer 17

Lesions anywhere in vestibular pathway

• peripheral disorders involving inner ear
• central disorders of brainstem of cerebellum

Question 18

How can you differentiate between peripheral and central disorders causing vertigo

Answer 18

Peripheral is MC

Central much worse

Question 19

Central cause of vertigo that require emergency treatment

Answer 19

Incipient brainstem stroke

Posterior floss hemorrhage

Question 20

Symptoms that might be indicative of posterior fossa disease

Answer 20

Diplopia
Visual change
Somatosensory changes
Weakness
Dysarthria
Incoordination
Impaired consciousness