Neuro3 Fitz Inner Ear

Front 1

Inner ear receptors have how many types? And what do they do?

Back 1

There are 2 types and convert mechanical energy to receptor potentials

Front 2

Type 1 hair cells are the true sensory receptors and convey info where?

Back 2

The brainstem

Front 3

Type 2 outer hair cells function as what???? basically motor units

Back 3

Biological amplifiers

Front 4

What allows the type 2 cells to contract?

Back 4

Lateral Cisternea (ER)

Front 5

Do type 1 and type 2 hair cells have different afferent and efferent innervations?

Back 5

YES

Front 6

Type 1 have what percentage of afferents? What is the ratio of hair cells to afferent?

Back 6

90% of the afferents for Type 1 hairs.

And they have a 1 hair cell/afferent

Front 7

Where do the efferents terminate on type 1?

Back 7

On the afferent terminals under the Inner hair cells

Front 8

Where do the efferents have contact with Type 2 hair cells?

Back 8

On the soma of the Outer Hair cells

Front 9

What supports type 2 contractile units in the cochlea

Back 9

Lateral cisternae

Front 10

Inner ear transduction is _____ where displacement toward the tallest stereocillia results in what??

Back 10

BIDIRECTIONAL results in depolarization

Front 11

What is positive deflection and what does it result in?

Back 11

Displacement towards the tallest stereocillia

Front 12

What results in hyperpolarization?

Back 12

Negative deflection, towards the scala tympani

Front 13

When does depolarization occur in the cochlea?

Back 13

When the basilar membrane moves toward the scala vestibuli

Front 14

If stereocillia dont work what happens?

Back 14

Sensory hearing loss. Can be because of noise and ototoxic

Front 15

Displacement towards the shortest row of stereocillia is?

Back 15

HYPERPOLARIZING and is toward the scala tympani

Front 16

What drugs can cause hearing loss?

Back 16

Aminoglycosides

Front 17

The decrease in receptor potential in response to a constant stimulus?

Back 17

Adaptation

Front 18

What exibits rapid adaptation? What exibits slower adaptation?

Back 18

Auditory hair cells........ Vestibular hair cells in saccule + utricle

Front 19

What continiously moves up and down the actin core of the tallest sterocillium to maintain tension on tiplink?

Back 19

ADAPTATION MOTOR

Front 20

What type of mysoin motor is only found in the inner ear and is implicated in hereditary deafness?

Back 20

MYOSIN 7A

Front 21

Adaptation also defines a set point so that some transduction channels are always open causing slight depol. of hair cells and basal release of NT, this allows negative displacements to reduce ??????

Back 21

Auditory nere firing

Front 22

The tiplink controls what?

Back 22

The opening and closing of the transduction channel

Front 23

What is the job of the semicircular canals?

Back 23

Detect head rotation (angular acceleration)

Front 24

The 2 otolith organs are?

Back 24

Utricle and Saccule

Front 25

What do the otolith organs do?

Back 25

Detect gravity (linear acceleration)

Front 26

What is the vestibular system responsible for?

Back 26

Balance and posture, coordination of head and body movements and in fixing the visual image on the fovea

Front 27

Vestibular system affects?

Back 27

Propriception and perception and eyes

Front 28

Major conflict of info from 3 systmes=

Back 28

vertigo, nausea, vomiting

Front 29

What are semicircular canals?

Back 29

Motion detectors

Front 30

What are Otolith organs (utricle and saccula)

Back 30

Gravity detectors

Front 31

Vestibular systems is integrated with other body sensations and they are not percieved as?

Back 31

Seperated

Front 32

What is the reference point when other sensory systems are in conflict?

Back 32

Reference postural signal

Front 33

Semicircular canals are dynamic and detect motion if _______?

Back 33

At rest or if head is moving at constant spead

Front 34

What fills the semicircular canals?

Back 34

Endolymph.

Front 35

What happens when the head is initially turned first step

Back 35

Endolymph remains in initial position due to inertia causeing movement of steriocilia against capula and altering receptor potential

Front 36

2nd step of head turing?

Back 36

Once head is moving at constant speed the duct fluid moves at same rate as the hair cells and steriocillia are NOT DEFLECTED

Front 37

What happens when the head stops?

Back 37

The fluid keeps moving and receptor potential is again altered this time in the opposite direction to what occured at the start of rotation

Front 38

Depolarization of the horizontal canals of the semicircular canal occurs when? For the Anterior and posterior canals depol. occurs where?

Back 38

When they move in the same direction. In the same direction as head tilt.

Front 39

What is the natural pairing? Left anteior with??

Back 39

Right posterior

Front 40

Horizontal canals: deflection of steriocillia towards ____ causes depol?

Back 40

Utricle

Front 41

If the head is going counterclockwise what direction are stereocilia going?

Back 41

Clockwise

Front 42

If the head goes left where does depol occur?

Back 42

Left horizontal canal

Front 43

What is the angle between anterior and posterior canals? What is it considered sagitally?

Back 43

90* and 41* from a sagital view

Front 44

Stereocillia are high in this electrolyte that causes depolarization?

Back 44

K+

Front 45

What is the bottom line for anterior and posterior canals?

Back 45

Same tilt=same depolarization

Front 46

So if I tilt my head forward and to the left what happens?

Back 46

Forward left depolarization and right posterior hyperpolarization

Front 47

Otolith organs detect? And are considered___? They cause CaCO3 particles to drag on what as head chages position?

Back 47

Gravity(linear accelartion) They are static and they drag CaCO3 on stereocilia

Front 48

When the body is in anatomical position the hair cells in_____ are nearly horizonatal with steorcillia invered____?

Back 48

Utricle is horizontal and stereocilia are vertical.

Front 49

The sensory epithelium in the saccule are vertical and the sterocilia are????

Back 49

Horizontal

Front 50

What determines directionality in the steriocillia?

Back 50

Orientation of hair cells

Front 51

What determines orientation of stereocillia in sensory epithelium?

Back 51

Striola

Front 52

The striola is what?

Back 52

A curved dividing ridge that runs thru the middle of the macula.

Front 53

In the utricle the kinocilia are orientated ???? to the striola and in the sacula ???? from it?

Back 53

Toward it in the utricle and away from it in the saccula

Front 54

Vestibular reflexes contain few synapses and are similar to spinal reflexes what are the 3 reflexes?

Back 54

Vestibulo ocular (VOR)
Vestibulospinal --Medial and lateral
Vestibulocerebellar

Front 55

What is the purpose of the VOR? So left head turn causes?

Back 55

Adjuct eye position to compensate for changes in head position.
Hyperpolarization and inhibition in the RIGHT. Depolarization and excitation in Left vestibular nuclie

Front 56

What does the inhibition in extraocular motor nuclei do for a left turn? For excitation? Causes

Back 56

Excites Left oculomotor and Right abducens nuclie and inhibits right oculomotor and left abducens. SO CONT of R lateral rectus, and left medial rectus.
MOVEMENT OF EYES TO RIGHT

Front 57

WHat is the bottom line of VOR?

Back 57

Rotate of head one direction cause contraction of extraocular muscles to slowly rotate eyes in opposite direction.

Front 58

VOR is responsible for what phase of nystagmus?

Back 58

SLOW phase (PURSUIT PHASE)

Front 59

Vestibulospinal Reflexes coordinate the position of head with trunk and body to maintain what?

Back 59

Head in an upright position during moment

Front 60

Function of VST system is apparent during what?

Back 60

Decerebrate rigidity

Front 61

LVST gets afferent source from? Does what?
MVST gets it from? Does what?

Back 61

Entire labyrinth (motion and gravity). Postural changes to compensate for tilts and movements of body.
Semicircular canals (motion) stablize head during walking

Front 62

Efferent connections and effect of LVST?

OF MVST?

Back 62

Ipsilateral, excititory

bilateral, excitatory and inhibitory

Front 63

How do the LVST control muscles?

Back 63

Contraction of extensor muscles (excite A and G motor neurons)

indirect relaxation of flexor muscles ( excitation of inhibitory interneurons)

Front 64

How do MVST control muscle?

Back 64

Relaxtation of muscles of upper back and neck (direct inhibition of alpha motor neurons)

Front 65

What does nystagmus consist of?

Back 65

Slow drift of eyes in one direction (Pursuit=VOR) And rapid recovery movement in opposite direction (SACCADE)

Front 66

How are nystagmuses named?

Back 66

For the fast direction.

Front 67

A right nystagmus means?

Back 67

The eyes drift to the left slowly and move quickly to the right.

Front 68

What controls the pursuit phase? What controls SACCADE?

Back 68

VOR,
Higher centers (cortex)

Front 69

Nystagmus is defined as?

Back 69

Rhythmical oscillation of eyeballs

Front 70

Nystagmus in the absence of vestibular stimulation indicates what?

Back 70

Some kind of pathology

Front 71

What is used to asses brain function? Cool water in the right ear will make??? What does warm water cause?

Back 71

Caloric test. Leftward nystagmus.
Warm causes the same side nystagmus

Front 72

If a patient is comatose what will be absent?

Back 72

The saccade

Front 73

IF a person is brain dead what will be absent?

Back 73

Both pursuit and saccade

Front 74

COWS?

Back 74

Cold water opposite
Warm water same

Front 75

Cold water in right ear causes what type of current? This does what to the stereocillia?

Back 75

Clockwise deflection to right same as if head moved to left

Front 76

Warm water causes what in the right ear?

Back 76

Counter clockwise current in semicircular canal. Stereocillia deflect to left. Same direction as head moved to the right

Front 77

Intensity and what determine what a person can hear?

Back 77

Frequency

Front 78

Intensity is found in what? and is defined as 20log(P/Po) with Po relative to normal?

Back 78

Decibels dB.

Front 79

What is dB SPL? What is dB HL or SL?

Back 79

Same reference at all levels. Different reference level at each level

Front 80

Complex sounds can be broken down into frequency via? What does this in the human ear?

Back 80

Spectral analysis. Cochlea

Front 81

The concept of linearity says that ?

Back 81

If you put 2 frequencies in you will get those 2 same frequencies out.

Front 82

In a nonlinear system such as the cochlea if you put in 2 freqeuncy components like 2kHZ and 5kHZ you get what out?

Back 82

4 readings. Such as 2,5,1,and 3

Front 83

Distortion products are produced by what??? And can be recorded as??

Back 83

Cochlea and otoacoustic emissions

Front 84

The middle ear functions to compensate for what????? If you lose function of ME what happens?

Back 84

loss of energy in air/water interface. External Ear to Cochlea Conductive hearing loss. 40-55 dB loss of sensitiveiy.

Front 85

How is energy loss minimized in the ME?? And how do you test it?

Back 85

Impedance matching. Rinne Test

Front 86

Impedance matching minimize energy loss by magnifiying the pressure delivered to the oval window relative to what?

Back 86

The pressure applied to the tympanic membrane

Front 87

Areal ratio, lever ratio, and buckling add together for?

Back 87

Impedance matching

Front 88

Areal ratio says that the TM > than oval window. While the lever ratio says the _____ > than the incus?

Back 88

Malleus

Front 89

What is buckling action?

Back 89

Force is transmitted from the center of the TM

Front 90

ME can't get perfect mass because of Acoustic impedance says that the effectivenss of transmitting vibration is??

Back 90

Frequency dependant.

Front 91

What 2 properties determine objects resonant frequency?

Back 91

MAss and Stiffness

Front 92

Mass means that ?

Back 92

Heavier objects vibrate at lower frequencies. Xylophone

Front 93

Stiffness means that?

Back 93

Less elastic objects vibrate at higher frequencies( stiffness limits low frequency transmission)

Front 94

The 2 factors in the ME that add to mass and stiffness?

Back 94

Ossicles with mass and middle ear space affects stiffness

Front 95

2 examples that change middle ear impedance and cause hearling loss?

Back 95

Otosclerosis and otitis media

Front 96

Otosclerosis is?

Back 96

Abnormal growth of bone in middle ear imobalizing stapes.

Front 97

What does otosclerosis cause? What are first affected?

Back 97

Bilateral gradual hearing loss. Higher frequency sounds affected first!!!!

Front 98

Otitis media is caused by? And What are effected first and then last?

Back 98

Middle ear infection that makes pus and fluid and inflamation. First to go are low frequency (speech) then HIgh frequency when mass of ME bones increases

Front 99

Whatever input the normal cochlea recieves it will detect. So in the absence of any sensorineural hearing loss are imposed by?

Back 99

Acoustic impedance of ME

Front 100

What do you need to detect lowest and highest frequency in the absolute test? What are audiograms determined by?

Back 100

LOUDER SOUND. Audiograms are determeined by ME

Front 101

What limits the high frequency transmissions? The low?

Back 101

Mass of ossicles. Stiffness of the ME cavity.

Front 102

Clinically thresholds are what instead of absolute? What is the main concern to people and doctors? Consonats have what? Vowels?

Back 102

Relative. Hearing of speech. High frequency. Low frequency

Front 103

Sound waves pass thru cochlea?

Back 103

Instantaneously.

Front 104

The travelling wave on the BM is established more gradually and is indepentent of how the motion is initiated which means it doesnt have to come thru the oval window but can use?

Back 104

BONE

Front 105

What does the traveling wave establish along the length of the cochlea?

Back 105

Frequency vs place relationships

Front 106

Where are high frequencies in cochle transduced??? Low frequencies?

Back 106

High at base, low at apex

Front 107

Transduction requires that the BM vibrate to induce steriocilla deflection in what?

Back 107

Hair cells

Front 108

Movement of hair cells is directional toward the scala vestibulis is?????/ Toward scala tympani?

Back 108

Depolarizing and hyperpolarizing

Front 109

What determines the peak for frequencies on the BM? This is both an active (energy requiring) and passive (structural process)

Back 109

resonant properties

Front 110

The peak of the travelling wave occurs at different places on the BM for each frequrency. High are where? Low are where?

Back 110

Base and the apex

Front 111

The base of the BM is nearest the?

Back 111

OVal window

Front 112

The middle ear transfer function determines the ____threshold of hearing at each frequency. The cochlea is so sensitive it can transduce any signal that reaches it.

Back 112

ABSOLUTE

Front 113

Low frequencies cause largest deflections where?? This is because of what?

Back 113

Apex because the BM is less stiff with greater mass.

Front 114

Higher frequencies produce the largest deflections at the base because?

Back 114

It is more stiff and less heavy

Front 115

What creates a positive feedback mechanism and what does it do?

Back 115

Outer hair cells use receptor potential to exert a force on the BM.

Front 116

The positive feedback mechanism does what? It results in?

Back 116

Amplifies the vibration of the membrane in a non linear higher frequency specific manner. A fluid wave which goes back to the perilymph vibrating ME apparatus and generating sounds that are emited from the ear

Front 117

Otoacoustic is what?

Back 117

Vibrating of the ME apparatus and generating sounds that are emitted from ear

Front 118

Active mechanical process is a type of enhanced frequency selectivity due to?

Back 118

Amplification of BM movement and increased sharpness of tuning

Front 119

What is the source of amplification in relation to hair cells?

Back 119

They come from the contractile properties of outer hair cells

Front 120

What is the first step in cochlear transduction? There are 5 steps total

Back 120

Sound induces traveling wave on BM

Front 121

The second step involves BM vibration causing?

Back 121

Stereocilia deflection

Front 122

Step 3... The mechanical stimulus is transduced and what are generated?

Back 122

Receptor potentials.

Front 123

What do receptor potentials lead to in IHC's?

Back 123

Neurotransmitter release which and AP generation in underly auditory nerve fibers

Front 124

What happens in OH cells whatn receptor potentials are made?

Back 124

Results in contraction which amplifies BM motion

Front 125

The increased motion of the BM results in?

Back 125

Positive feedback

Front 126

What efferently innervates the OHC?

Back 126

Superior Olivary complex

Front 127

The CNS has the ability to adjust the amount of feedback provided to the BM this allows the CNS to change?

Back 127

Sensitivity and frequency selectivitly of the cochlea

Front 128

Otoacoustic emissions are what?

Back 128

Sounds from your ear when it is working normally

Front 129

Sounds that are recorded from the external ear canal that are generated by NORMAL cochlea as a result of nonlinear processing cause by NORMAL OHC function this is?

Back 129

Otoacoustic emissions

Front 130

What is the deal with Otoacoustic emissions, how are they made? This isn't the same as tinnitus

Back 130

They are generated either spontaneously or evoked by sounds

Front 131

How can you use OAE?

Back 131

Use it to test hearing in non-invasive, non behavioural manner.

Front 132

What can you use to test OAE?

Back 132

Clicks or individual frequencies both will evoke emissions

Front 133

What is endolymph?

Back 133

It is a substance high in K+ which resides in on top of hair cells

Front 134

Where is endolymph made?

Back 134

Stria Vascularis

Front 135

What is the endococlear potential?

Back 135

+80 mv

Front 136

What is the stria vascularsi similar to?

Back 136

The kidney

Front 137

Loop diurectis are toxic to the kidney since they affect K/Na/Cl transports this means they affect?

Back 137

The stria vascularis too

Front 138

Why is endolymph unique?

Back 138

It has 150 mM K+ to 1mM Na

Front 139

What is the endocochlear potential?

Back 139

Difference between scala tympani and scala media +80mV

Front 140

Are hair cell transduction channels selective or non selective to cations?

Back 140

Non selective

Front 141

Transduction occurs by allowing K to flow into what and cause them to what?

Back 141

Transduction channels open allowing K to flow ino hair cells and cause depolaraization.

Front 142

Depolarization of hair cells is due to what?

Back 142

The large electrochemical gradient between endolymph and hair cell intracellular fluid

Front 143

What characteristics allow for the extensive electrochemical gradient to occur ?

Back 143

Reticular lamina, tight juntions

Front 144

How is K gotten back to the stria vascularis?

Back 144

K+ recycling system that allows the uptake of K ions

Front 145

What is the most common form of inherited sensorineural deafness related to tight junctions?

Back 145

Connexin proteins are genetically flawed

Front 146

What drug hurts the inner ear as well as the kidney?

Back 146

Furosemide- loop diuertics

Front 147

What do loop diuertics like furosemid do?

Back 147

Block Na/K/Cl transport and decrease EP, and raise acoustic thresholds

Front 148

Alll the pathways central to the cochlear nucleus are______ this is imortant for understanding sound localization?

Back 148

Bilateral

Front 149

What is special about auditory pathways that ensure precise timing of acoustic signals?

Back 149

Myelinated and have ion channels and receptor specializations

Front 150

Auditory brainstem responses are recorded via _____ in response to repeated presentations of sounds of specific frequency and intensity.

Back 150

EEG

Front 151

The lateral superior olive localizes what??

Back 151

High frequency stimuli

Front 152

How does Lateral superior olive neurons localize high frequency stimuli?

Back 152

Comparing interaural intensity differences

Front 153

THe medial superior olive localizes what?

Back 153

Low frequency stimuli

Front 154

How does the medial superior olive localize low frequency stimuli?

Back 154

Interaural time differences

Front 155

What recieves input from both cochlear nuclie?

Back 155

Superior olivary nucleas

Front 156

Louder in one ear than the other?

Back 156

Interarual intesity difference

Front 157

Reaches one ear first?

Back 157

Interal timing differences.

Front 158

Sounds arrive sooner at closer ear are what? determined by?

Back 158

Low frequency *MSO

Front 159

Sounds are louder in closer ear?

Back 159

High frequency