5. Physiology of Auditory and Vestibular Systems Flashcards

1
Q

What is the ion distribution for endolymph?

A

High [K+}

Low [Na+]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the ion distribution for perilymph?

A

Low [K+]

High [Na+]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where do higher frequency sounds displace the basilar membrane?

A

Near oval window where basilar membrane is narrow and stiff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where do low frequency sounds displace the basilar membrane?

A

Near helicotrema (tip of cochlea) where the membrane is wide and flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What CN transmits central axons from the primary auditory neurons of the spiral ganglion to the brainstem?

A

CN VIII (vestibulocochlear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What mechanoreceptors are rich in actin?

A

Hair cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What motion of the hair cell stereocilia causes depolarization?

A

Deflection towards the Kinocilium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What motion of the hair cell stereocilia causes hyperpolarization?

A

Deflection away from the kinocilium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What neurotransmitter is released by the hair cells?

A

Glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What channel on the stereocilia allows entry of K+?

A

TRPA1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What part of the cochlea is the stria vascularis located in? What is its function?

A

Scala media

Maintains electrochemical properties of endolymph by pumping K+ in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What cells act as the primary source of auditory information?

A

Type 1/Inner hair cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the function of the 3 rows of outer hair cells?

A

Act as amplifier, boost mechanical vibrations of basilar membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What protein allows outer hair cells to be contractile?

A

Prestin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the source of otoacoustic emissions?

A

Outer hair cells (Type II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of hair cells both send afferent neurons and receive efferent neurons?

A

Outer hair cells (send Type II afferents)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What hair cells send Type I afferent neurons?

A

Inner hair cells

18
Q

What is the function of the dorsal cochlear nuclei?

A

Integrate acoustic information with somatosensory information to localize sound

19
Q

What is the function of the ventral cochlear nuclei?

A

Process temporal and spectral features of sound

20
Q

What part of the brainstem is the first site where information from both ears converge? What is this convergence called?

A

Superior olivary complex

Binaural processing

21
Q

What structure is important for generating a map of interaural intensity differences to localize sound?

A

Lateral Superior Olivary Nucleus

22
Q

What structure is important for generating a map of interaural time differences to localize sound?

A

Medial Superior Olivary Nucleus

23
Q

Which colliculus is involved in localizing sound vertically? Horizontally?

A

Superior colliculus - Vertical

Inferior colliculus - Horizontal

24
Q

What is the role of the medial geniculate nucleus of the thalamus in the auditory pathway?

A

Processing speech inflection

25
Q

What is the role of the primary auditory cortex in the auditory pathway?

A

Conscious perception of sound (volume, rate of frequency modulation)

26
Q

What region of the primary auditory cortex responds to low frequency? High frequency?

A

Rostral responds to low frequency

Caudal responds to high frequency

27
Q

What areas are contained within the auditory (secondary) association cortex (A2)?

A

Broca’s, Wernicke’s

28
Q

Which hair cells receive medial olivocochlear efferents?

A

Outer hair cells

29
Q

What efferent fibers do the inner hair cells receive from the superior olivary complex?

A

Lateral olivocochlear efferent fibers

30
Q

What efferent input fibers are responsible for reducing the response to noise and shifting response to higher sound levels?

A

Olivocochlear Efferents

31
Q

What parts of the middle ear send efferents to the auditory system? From what cranial nerves?

A

Tensor Tympani to malleus (CN V)

Stapedius to stapes (CN VII)

32
Q

What is the main function of middle ear efferents?

A

Prevent damage - decrease transmission of sound (act at low frequencies)

33
Q

Evoked otoacoustic emissions are used for what?

A

Test for hearing loss in newborns (no emissions if damage present)

Tinnitus

Ototoxicity

34
Q

Damage to what structures causes sensorineural hearing loss?

A

Outer hair cells, especially at the base end (high frequency) of the cochlea

35
Q

Damage to what structures will cut off sensorineural auditory input to the CNS?

A

Inner hair cells

36
Q

What is a cochlear prosthesis?

A

Electrode array threaded through the cochlea to stimulate nerve fibers and provide sound

37
Q

What types of rotation are detected by the horizontal, posterior, and anterior semicircular canals?

A

Horizontal - rotation in horizontal plane

Vertical - rotation backwards in the vertical plane (falling backwards)

Anterior - rotation forwards in the vertical plane (falling forward)

38
Q

When falling backward, what is the reflex of the eye muscles?

A

Posterior semicircular canal detects falling backward => Superior oblique M. is activated, inferior oblique inhibited => Eyes move down to maintain gaze on horizon

39
Q

When falling forward, what is the reflex of the eye muscles?

A

Anterior semicircular canal detects falling forward => Superior rectus m. activated, inferior rectus muscle inhibited => Eyes move up to maintain gaze on horizon

40
Q

What is the basic action of cortex and cerebellum on the vestibulooptic reflex?

A

Inhibitory - allows for voluntary motion