Chapter 11: The Auditory and Vestibular Systems Flashcards
(98 cards)
1
Q
Sense of hearing: ()
A
audition
2
Q
Sense of balance: ()
A
vestibular system
3
Q
visible portion of the ear; consists of cartilage covered by skin -> forms a sort of funnel that helps collect sound from a wide area
A
pinna
4
Q
shape of pinna makes us more sensitive to sounds (ahead/behind) us
A
ahead
5
Q
Entrance to internal ear
A
auditory canal
6
Q
End of auditory canal
A
tympanic membrane
7
Q
Series of bones (smallest bones in the body)
A
ossicles
8
Q
ossicles transfer movements of tympanic membrane into movements of () -> 2nd membrane; covers a hole in the skull
A
oval window
9
Q
fluid-filled compartment located behind oval window; contains apparatus for transforming physical motion of oval window membrane into a neuronal response
A
cochlea
10
Q
() in the cochlea send signals to brain stem neurons in response to sound detection
A
auditory receptors
11
Q
in response to signals from cochlea, brain stem neurons then bring info to ()
A
medial geniculate nucleus (MGN)
12
Q
MGN projects to () located in temporal lobe
A
primary auditory cortex (A1)
13
Q
bones classified as ossicles
A
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
14
Q
ossicle connected to tympanic membrane and incus
A
malleus
15
Q
the incus forms a (rigid/flexible) connection to stapes
A
flexible
16
Q
the stapes has a flat bottom portion called a ()
A
footplate
17
Q
Connects air in middle ear and air in nasal cavities
Valve keeps it closed; opening of valve equalizes air pressure between middle ear and nasal cavities
A
Eustachian tube
18
Q
Response when onset of loud sound causes tensor tympani and stapedius muscle contraction (makes the chain of ossicles become rigid)
A
attenuation reflex
19
Q
(): anchored to Malleus on one end and the cavity of the middle ear on the other end
A
Tensor tympani muscle
20
Q
(): a fixed anchor of bone and stapes
A
Stapedius muscle
21
Q
function of the attenuation reflex
A
adapts ear to loud sounds, protects inner ear, enables us to understand speech better
22
Q
When ossicles chain becomes rigid, sound conduction to inner ear is greatly (amplified/diminished)
A
diminished
23
Q
Three fluid-filled chambers of the cochlea
A
Scala vestibuli
Scala media
Scala tympani
24
Q
() – separates s. vestibuli and s. media in cochlea
A
Reissner’s membrane
25
() – separates s. tympani from s. media in cochlea
Basilar membrane
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()– holes in membranes; connects s. tympani and s. vestibuli in cochlea
Helicotrema
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() – contains auditory receptor neurons in cochlea
Organ of Corti
28
() membrane – located above Corti
Tectorial
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(): fluid in scala vestibuli and scala tympani (low K+ and high Na+: similar to CSF)
Perilymph
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(): fluid in scala media (high K+ and low Na+: similar to intracellular fluid)
Endolymph
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(): endolymph electrical potential 80 mV more positive than perilymph
Endocochlear potential
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the Endocochlear potential is caused by ()
Caused by ion difference and permeability of Reissner’s membrane
33
() – endothelium lining one wall of the scala media; contacts the endolymph; Where active transport processes take place to maintain different ion contents between perilymph and endolymph
Stria vascularis
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stria vascularis absorbs (1) from and secretes (2) into endolymph
1. Na+
2. K+
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At high freq., stiffer base of membrane vibrates -> ()
dissipates most of the sound energy and wave doesn’t travel very far
36
() sounds generate waves that travel all the way to the floppy apex before energy is dissipated
Low freq.
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The response of basilar membrane establishes a place code in which ()
different location of membrane are maximally deformed at different sound frequency
38
Systemic organization of sound frequency within the auditory structure: ()
tonotopy
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Specialized epithelial cells with stereocilia
hair cells
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hair cells are sandwiched between the (1) and the (2)
1. basilar membrane
2. tectorial membrane
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organization of inner and outer hair cells
Three rows of outer and one rows of inner hair cells
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() are also found between the basilar and tectorial membranes; provide structural support
rods of Corti
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Hair cells form synapses on neurons whose cell bodies are located in the spiral ganglion (w/in ())
modiolus
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hair cell synapses have axons which enter the auditory nerve -> branch of the ()
auditory-vestibular nerve (CN VIII)
45
() of stereocilia is a critical event in sound transduction into a neural signal
Bending
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Cross-link filaments make the stereocilia stick to one another -> all the cilia move as ()
one unit
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Upward movement of the basilar membrane
: the reticular lamina moves up and in toward the modiolus -> stereocilia bend ()
outward
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Downward movement of the basilar membrane
: the reticular lamina moves down and away from the modiolus -> stereocilia bend ()
inward
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A stiff filament () connects each channel to the upper wall of the adjacent cilium.
tip link
50
When the cilia are (), the tension on the tip link causes the channel to spend part of the time in the opened state, allowing a small amount of K+ from the endolymph to move into the hair cell.
pointing straight up
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() the cilia changes tension on the tip link, either closing or opening the channels.
Displacing
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The innervation of hair cells: One spiral ganglion fiber synapses with (one/multiple) inner hair cell (95 % of the SGN)
one
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The innervation of hair cells: one SGN synapses with (one/multiple) outer hair cells
multiple
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The vast majority of the information leaving the cochlea comes from (inner/outer) hair cells.
inner
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outer hair cells serve as () in sound transduction
cochlear amplifier
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Motor proteins () in the membrane of the outer hair cells
Prestin
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Outer hair cells respond to sound with both a (1) and a (2).
1. receptor potential
2. change in length
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When the outer hair cells amplify the response of the basilar membrane, the stereocilia on the inner hair cells (), producing a greater response in the auditory nerve (100X).
bend more
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Stimulation of efferent fibers projecting from brain stem towards the cochlea causes release of () -> changes shape of outer hair cells and affects responses of inner hair cells
ACh
60
() temporarily decreases transduction that normally results from bending of stereocilia on hair cells
Furosemide
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Auditory nerve supplies info from spiral ganglion cells to (1) and also to (2), which directly innervates inferior colliculus (midbrain)
1. ventral cochlear nucleus
2. dorsal cochlear nucleus
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(): frequency at which a neuron is most responsive—from cochlea to cortex; can vary among neurons
Characteristic frequency
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Recording response beyond brain stem result in more ()
complex patterns
64
Encoding information about stimulus intensity: (2)
Firing rates of neurons
Number of active neurons
65
Loudness perceived is correlated with ()
number of active neurons.
66
Depending on location of basilar membrane, maximal freq. that can be detected varies -> high freqs. are detected closer to ()
base
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Spatial patterns of the () of the basilar mem. are preserved in spiral ganglions and brain stem
tonotopic map
68
From the base to apex, basilar membrane resonates with increasingly (higher/lower) frequencies.
lower
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Tonotopy is preserved in the (2)
auditory nerve and cochlear nucleus.
70
(): the pooled activity of a number of neurons, each of which fires in a phase-locked manner.
Volly principle
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() is where neurons only fire at preferred phases in each cycle (usually amplitude peak)
phase locking
72
At low frequencies, we detect pitch using the () from neurons
pattern of AP firing
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At higher freqs, pitch is determined by () (neurons only randomly fire at random phases -> no phase locking)
tonotopy
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(): difference in time for sound to reach each ear
(low frequency cases: 20-2000Hz)
Interaural time delay
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(): sound at one ear less intense because of head’s sound shadow
(high frequency cases: 2000-20,000Hz)
Interaural intensity difference
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Neurons in the cochlear nuclei are (1) neurons, whereas all later stages (starting from superior olive) are (2) neurons
1. monaural
2. binaural
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Monoaural – receive info from ()
only 1 side
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AP converge on a superior olive neuron which responds most strongly if their arrival is()
coincident
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Vertical sound localization based on ()
reflections from the pinna
80
Axons leaving MGN project to auditory cortex via internal capsule in array called ().
acoustic radiation
81
Neuronal response properties: () running mediolaterally across A1 cortex
Isofrequency bands
82
() lesion in auditory cortex: almost normal auditory function (unlike lesion in striate cortex: complete blindness in one visual hemifield)
Unilateral
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in the primary auditory cortex, different frequency bands are processed in ()
parallel (independently processed)
84
the vestibular system evolved from the () in aquatic vertebrates
lateral line organs
85
main components of the vestibular labyrinth
1. otolith organs
2. semicircular canals
86
() are responsible for detecting gravity and tilt; changes in head angle and linear acceleration
otolith organs
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() are responsible for detecting head rotation and angular acceleration
semicircular canals
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the vestibular system uses (), like auditory system, to detect changes
hair cells
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Info from hair cells in vestibular system is transmitted to brain via ()
vestibular nerve
90
() – calcium carbonate crystals that respond to gravity changes; cause tilting of stereocilia in response to gravity
Otoconia
91
the () hair cells in the otolith organs respond to tilt
macular
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each macular hair cell has one tall cilium called a ()
kinocilium
93
The bending of hairs toward to the kinocilium results in a () receptor potential.
depolarizing, excitatory
94
Bending the hairs away from the kinocilium () the cells.
hyperpolarizes and inhibits
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macular orientation: The (1) are oriented vertically, while the (2) are horizontal.
1. saccular maculae
2. utricular maculae
96
there are () semicircular canals on each side
3
97
Functions to fixate line of sight on visual target during head movement
Vestibulo-Ocular Reflex (VOR)
98
mechanism of Vestibulo-Ocular Reflex (VOR):
senses rotations of head, commands compensatory movement of eyes in opposite direction
