Auditory System 2 (Section 4)

Question 0

Cell bodies of auditory CN VIII neurons lie in what ganglion

Answer 0

Spiral ganglion

Question 1

The mechanical deformation of the hair cells on the basilar membrane causes what?

Answer 1

The opening of ion channels in the hair cells

Question 2

What is responsible for the transduction process in the ear

Answer 2

Hair cells

Question 3

WHere do the axons of the auditory CN VIII terminate?

Answer 3

Cochlear nuclei

Question 4

What part of the cochlea receive high frequency sounds

Answer 4

Base of the cochlea

Question 5

Apex of cochlea have what frequency of sounds

Answer 5

Low frequency sounds

Question 6

Which portion of the cochlea have stereocilia that are short and stiff

Answer 6

Base of the cochlea

Question 7

Hair cells at apex are twice as long as base of cochlea

Answer 7

True

Question 8

How many rows of hair cells are on the inner part

Answer 8

Single row

Question 9

How many hair cells are on the outer part

Answer 9

Three rows

Question 10

Action potentials traveling down the central process of the cochlear nerve reach what nuclei?

Answer 10

Dorsal and Ventral cochlear nuclei in the Medulla

Question 11

Fibers in the 8CSLIMA pathway decussate where?

Answer 11

Lower pons and ascend in the lateral lemniscus

Question 12

Of those fibers that decussate in the 8CSLIMA pathway where do they synapse?

Answer 12

Superior Olivary Nuclear complex

Reticular Formation

Question 13

Some fibers ascend uncrossed in what?

Answer 13

Ipsilateral lateral lemniscus

Question 14

A unilateral lesion of the central auditory pathway causes more hearing loss on which side of lesion

Answer 14

Contralateral or the opposite side of the lesion

Question 15

Fibers in the lateral lemniscus (8CSLIMA) synapse where?

Answer 15

Inferior colliculus

Question 16

After synapsing in the Inferior Colliculus, axons go to what part of the diencephalon?

Answer 16

Medial Geniculate

Question 17

Neurons in the medial geniculate send axons to where?

Answer 17

Primary Auditory Cortex (Brodmann’s areas 41 and 42)

Question 18

Primary auditory cortex functions how?

Answer 18

Conscious hearing of sound

Question 19

Superior Olivary nucleus and Inferior Colliculus function

Answer 19

Orientation/localization of sound

Question 20

Reticular Formation function

Answer 20

CNS activation/alertness

Question 21

Tensor Tympani muscle is innervated by what nerve?

Answer 21

CN V

Question 22

Tensor Tympani muscle function

Answer 22

Dampen vibration of tympanic membrane in response to loud noise

Question 23

Nerve and function of Stapedius muscle

Answer 23

CN VII

Function to dampen vibration of stapes in response to loud noise

Question 24

Conductive deafness is:

Answer 24

Caused by interruption of the passage of sound waves through the external or middle ear

Question 25

Three things that can contribute to conductive deafness

Answer 25

1. Obstruction by a foreign body in the external auditory meatus
2. Otosclerosis - fixation of the stapes due to excessive bone growth
3. Otitis media - inflammation of middle ear. Common cause of meningitis and most common cause of brain abscesses

Question 26

Sensorineural deafness - 5 causes

Answer 26

1. Disease of the cochlea, CN VIII, or the central auditory connections
2. Action of drugs and toxins
3. Rubella infection in utero, syphilis…
4. Presbycusis - hearing loss that occurs with aging
5. Acoustic neuroma - tumor of CN VIII

Question 27

How would a tumor affect hearing?

Answer 27

A tumor of CN VIII in the cerebellopontine angle, near the brainstem exit of CN VIII

Question 28

2 causes of Hyperacusis

Answer 28

1. Damage of CN V preventing tympani muscle from dampening sounds
2. Damage to CN VII preventing stapedius muscle from dampening sounds

Question 29

What is Tinnitus?

Answer 29

Abnormal sounds (ringing, hissing, roaring, buzzing, or humming)

Question 30

4 causes of Tinnitus

Answer 30

Acoustic neuroma
Irritation of spiral organ of Corti in the cochlea
Irritation of CN VIII
Overproduction of endolymph

Question 31

Meniere’s Syndrome cause

Answer 31

overproduction of endolymph or inability to absorb endolymph

Question 32

Unilateral lesion of ascending auditory pathway causes?

Answer 32

bilateral diminution of hearing but MORE marked on contralateral side