Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuro Exam 3 > Physiology of the Auditory and Vestibular Systems > Flashcards

Physiology of the Auditory and Vestibular Systems Flashcards

1
Q

What is endolymph? Where is it found?

A

POTASSIUM-RICH fluid
Similar in concentration to CSF and ICF - high K, low Na

Found: 
Cochlear duct 
Membranous labyrinth
Scala media
Bathes the apical side of hair cells
Inside vestibular apparatus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is perilymph? Where is is found?

A

POTASSIUM-POOR fluid
Similar in concentration to ECF - low K, high Na

Found: 
Bathes basal end of hair cells 
Scala vestibuli 
Scala tympani 
Surrounds vestibular apparatus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does sound travel through the ear roughly?

A

Sound waves enter the external ear and go through the auditory canal.

They bounce of the TM and cause movement in the Malleus, Incus, and Stapes.

Stapes causes movement of the oval window.

Sound travels through the perilymph in the Scala vestibuli, through the endolymph in the Scala media, and then through the perilymph in the Scala tympani. All of this causes movement of the basilar membrane.

Ultimately, sound hits the round window.

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

Where does high frequency sound hit the basilar membrane?

A

Towards the base of the cochlea, closer to the oval window. It is narrow and stiff.

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

Where does low frequency sound hit the basilar membrane?

A

Farther along the cochlea, where it spirals. It is more wide and bendy.

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

What type of receptors are hair cells?

A

Mechanoreceptors - convert mechanical signal to electrical

They receive afferent and efferent input but are not neuronal.

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

What happens when sterocilia bend TOWARD kinocilium?

A

This opens up K+ channels, causing a influx of K+ leading to DEPOLARIZATION of the hair cell = excitation.

Voltage gated Ca2+ channels will then open up leading to release of vesicles filled with excitatory neurotransmitters –> triggers afferent nerve.

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

What 2 factors are required for the electrochemical drive that stimulates nerve fibers?

A

Large endolymphatic potential = K+ concentration gradient

Large electrical gradient = scala media has high positive charge

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

How are the sterocilia linked to each other? How are they linked to the kinocilium?

A

The sterocilia are linked through tip and ankle links.

They are connected to the kinocilium through kinociliary links.

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

What is is the excitatory neurotransmitter released onto the 8th nerve fibers form the hair cell?

A

Glutamate

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

What happens when sterocilia deflect in the opposite direction of the kinocilium?

A

Hyperpolarization of hair cell

Inhibition

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

Name the ion channel on the tips of the sterocilia.

A

TRPA1 (K+ channels)

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

What is the electrochemical gradient of the scala media vs. scala tympani and vestibuli?

A

Scala media = +80 mv

ST and SV = 0 mv

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

What maintains the electrochemical properties of scala media? [

A

Stria Vascularis

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

Describe the orientation of hair cell on basilar membrane.

A

One row of Inner hair cells

3 rows of outer hair cells

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

What is the function of the inner hair cells?

A

Primary source of auditory information

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

What is the function of the outer hair cells?

A

Act as amplifiers of sound

Boost mechanical vibration of the basilar membrane

Contractile

Otoacoustic emissions

Sensitivity and tuning of responses are susceptible to injury of outer hair cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is the afferent and efferent innervation for hair cells coming from?

A

Afferent = Spiral ganglion

Efferent = Superior olivary complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of afferent innervation do inner and outer hair cell have?

A

Inner hair cells = Type 1 afferents (95%) - 1+ neurons from ONE hair cell to brainstem

Outer hair cells = Type 2 afferents - SINGLE neuron from MULTIPLE hair cells to brainstem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Tell me the specific details of what happens in the cochlea once sound hits the oval window.

A

Scala vestibuli pressure falls below Scala tympani

Basilar membrane bows upward

Organ of corti shears toward hinge of tectorial membrane

Hair bundles of outer hair cells tilt toward longer stereovilli

Transduction channels open in outer hair cells

Depolarization contracts motor protein prestin.

Contraction of outer hair cell accentuates upward movement of basilar membrane (makes waves in endolymph)

Endolymph waves beneath tectorial membrane

Inner hair cells bend toward longer stereovilli

Transduction channels open in inner hair cells

Depolarization opens voltage gated Ca2+ channels

Synaptic vesicles fuse, releasing glutamate

21
Q

What is the first structure where information from both ears converge to localize sound?

A

Superior olivary complex - binaural processing

22
Q

What are the 2 nuclei of the superior olivary complex? What are they responsible for?

A

Medial superior olivary nucleus:
Maps the interaural TIME differences - based on which ear it hit first

Lateral superior olivary nucleus:
Maps the interaural INTENSITY differences

23
Q

What is the superior colliculus responsible for when its comes to mapping sound location?

A

It takes location data from the inferior colliculus and adds VERTICAL HEIGHT

Spatial map of sound

24
Q

What is the inferior colliculus responsible for when its comes to mapping sound location?

A

It suppresses information related to echoes

25
Q

How is the medial geniculate nucleus important in the auditory pathway?

A

It is a relay station with lost of convergence form distinct spectral and temporal pathways

Allows for processing FEATURES OF SPEECH INFLECTIONS

26
Q

How is the primary auditory cortex (A1) important in the auditory pathway?

A

Essential in CONSCIOUS PERCEPTION of SOUND

Higher order process of sound - loudness, frequency, etc.

27
Q

In the primary auditory cortex, relate input area to sound frequency.

A

Rostral areas are activated by low frequency of sound

Caudal areas = high frequencies

28
Q

What is the auditory association cortex responsible for?

A

Contains Broca’s and Wernike’s areas

Responds to more complex sounds, identifying sounds and speech

29
Q

What consists of efferent input to the auditory system?

A

Olivocochlear efferents

Middle ear muscle motoneurons

Autonomic innervation to inner ear

30
Q

What do olivocochlear efferents come from and what do they innervate?

A

Originate in superior olivary complex

Medial OC = outer hair cells

Lateral OC = inner hair cells

31
Q

What are olivocochlear efferents responsible for?

A

Shifts responses to higher sound levels

Decreases adaptation

Reduces response to noise

May protect hair cells from damage to intense sound

32
Q

What are the middle ear efferents?

A

Tensor tympani to malleus = CN 5

Stapedius to stapes = CN 8

33
Q

What are middle ear efferents responsible for?

A

B/L response to high sound levels

Contractions decrease transmission of sound

Act at low frequencies

May prevent damage

May prevent low frequency masking = improving speech discrimination

34
Q

What are otoacoustic emissions?

A

It’s when the ear emits sounds

Usually low intensity

35
Q

What are the 2 types of otoacoustic emissions? Describe the 2 types.

A

Two types - spontaneous and evoked

Spontaneous:
pure tones usually
probably generated from motile outer hair cells

Evoked:
used to test for hearing loss - no emissions are evoked if damage is present

36
Q

How are otoacoustic emissions clinically important?

A

Used for newborn hearing screen

Tinnitus

Ototoxicity - drug or chemical damage to inner ear

37
Q

Describe sensorineuronal hearing loss. What parts of the ear are more susceptible to it?

A

Caused by damage to hair cells or nerve fibers

Base end of cochlea more susceptible than apical
OHCs more susceptible than IHCs

38
Q

What happens if you have injury to the outer hair cells?

A

Decrease in sensitivity and broader tuning

39
Q

What happens if you have injury to the inner hair cells?

A

Cuts of auditory input to CNS

40
Q

What is cochlear prosthesis?

A

Multiple electrode array threaded through cochlea to stimulate surviving nerve fibers

41
Q

What is angular acceleration?

A

Motion involving rotation around one or more planes

Ex: spinning, falling forward/backward

42
Q

What is linear acceleration?

A

Motion in the horizontal and vertical plane

43
Q

What part of the ear detects angular acceleration?

A

Semicircular canals:
anterior = falling forward
posterior = falling backward
horizontal = motion around horizontal plane

44
Q

What part of the ear detects linear acceleration?

A 
Utricle = forward and backward 
Saccule = up and down
45
Q

During angular acceleration, what happens to our eyes?

A

Our reflexes keep our eyes on the horizon (spot directly in front of us)

If you fall back, eyes move down
If you fall forward, eyes move up

46
Q

When you are spinning, what muscles in the eye are being activated?

A

Medial rectus and contralateral lateral rectus

For example, if you are spinning RIGHT your RIGHT medial rectus is being activated + LEFT lateral rectus.

47
Q

If you are falling back and your posterior semicircular canal is activated, what muscles in the eye are being activated?

A

Superior oblique activated

Inferior oblique inhibited

48
Q

If you are falling forward and your anterior semicircular canal is activated, what muscles in the eye are being activated?

A

Superior rectus activated

Inferior rectus inhibited

Neuro Exam 3 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions