Neuroanat 8

Front 1

Inner ear characteristics

Back 1

noncompressible fluid, converts sound into neural energy (mechanical to electrical),

Front 2

Inner ear basilar membrane response to high frequencies

Back 2

It is smaller and stiifer

Front 3

Inner ear basilar membrane response to low frequencies

Back 3

wider and more flexible

Front 4

Organ of Corti cells

Back 4

Inner and outer hair cells

Front 5

- Inner hair cells are

Back 5

AFFERENT – account for 90% of afferent nerve fibers and give rise to sound perception

Front 6

Outer hair cells are

Back 6

EFFERENT – lots of efferent input onto them to modulate sound, 10% of afferent input

Front 7

- Deflection of hair cells towards kinocilium leads to

Back 7

depolarization -> influx of K from kendolymph -> depolarization leads to opening of voltage gated Ca channels -> influx of Ca -> Ca triggers NT release

Front 8

Transmission of sound occurs from

Back 8

air into fluid filled inner ear via ear drum and middle ear ossicles

Front 9

Cochlea characteristics

Back 9

curved apparatus, displacement of microvilli of hair cells results in change of potential across hair cell membrane

Front 10

Hair cells are attached to basilar membrane of cochlea and here they

Back 10

vibrate in response to pressure and waves

Front 11

90% nerve fibers in the organ corti account for and and give rise

Back 11

afferente cells
give rise to sound and perception

Front 12

Cochlea features

Back 12

curved apparatus, displacement of microvilli of hair cells results in change of potential across hair cell membrane

Front 13

In the cochlea - Hair cells are attached to basilar membrane, which vibrates in response to

Back 13

pressure sound waves

Front 14

- Length and mass of basilar membrane in cochle results in

Back 14

tonotopic organization with high frequencies closer to base of cochlea and low frequencies at apex

Front 15

- Localization of sound is depending upon comparing time of arrival in each ear and relative at each ear, the comparisons take place as follows

Back 15

o First comparison of sound from both ears at the superior olivary nucleus
o First relay at dorsal and ventral cochlear nuclei – several relay sites on way to cerebral cortex

Front 16

transmission of sound path

Back 16

: hair cells -> cochlea -> primary neurons -> dorsal and ventral cochlear nuclei ->superior olive (bilateral) ->(lateral lemniscus) ->inferior colliculus ->(brachium of inferior colliculus) -> MGN -> transverse gyri of Heschl on temporal lobe

Front 17

- Coclear nuclei gets unilateral input and project bilaterally to

Back 17

superior olive
o Decussation occurs in trapezoid body – located in pons

Front 18

- Sound info travels from superior olive to

Back 18

inferior colliculus in the lateral lemniscus

Front 19

- Sound info travels from inferior colliculus to

Back 19

MGN through brachium of inferior colliculus

Front 20

Sound localization occurs at

Back 20

- Superior olivary nucleus and it is the first bilateral input

Front 21

timing difference of sound occurs at

Back 21

Medial superior olive

Front 22

Intense density of sound occurs at

Back 22

Lateral superior olive

Front 23

- Unilateral deafness – caused by

Back 23

damage to middle ear, cochlea, or auditory nerve – “lower” than superior olive

Front 24

- Unilateral lesion above superior olive causes

Back 24

bilateral decrease in hearing

Front 25

What nerves get affected of theres a tumor in the internal acoustic meatus?

Back 25

7.8.9

Front 26

There are three comparments in the cochlea with spiral ganglion

Back 26

Scala Vestibuli
Scala Tympani
Scala Media

Front 27

Perlymph in the cochlea is high in

Back 27

Na and it is the extracellular comparment of the cochlea similar to plasma and CSF

Front 28

Endolymph in the cochlea is high in

Back 28

K

Front 29

Stria Vascularis of cochlea

Back 29

secretes K for endolymph

Front 30

The fact that endolymph has a high K concentration means

Back 30

that K not Na causes the depolarization current

Front 31

Solitary hair cells characterisitcs

Back 31

-have stereocillia on top
-Extremely sensitive to sheering

Front 32

In both inner and outer hair cells the links between stereocillia increase

Back 32

the open probability of transduction channels when a shearing force is applied directed towards the tallest stereocillia in the bundle

Front 33

Depolarization of outer hair cells generate length changes that are coupled into

Back 33

organ of corti and basilar membrane motion

Front 34

At the basilar membrane of organ of corti the highest vibrations are at the

Back 34

stapes

Front 35

at the basilar membrane of organ of corti the lowest vibrations occur at

Back 35

helicotrema

Front 36

vibration of different regions of the organ of corti as a response to either HF or LF lead to

Back 36

tonotopic organization along the length of the basilar membrane

Front 37

Membraneous labyrinth contains

Back 37

the peripheral auditory apparatus

Front 38

CN VIII contains

Back 38

afferents as well as efferent fibers

Front 39

topographies of connections provides insights into

Back 39

the functions of ascending pathways

Front 40

Auditory brainstem pathways ascend in the

Back 40

lateral lemniscus

Front 41

Medial geniculate, the laminated division is where

Back 41

theres tonotopical organization and where modalities mix

Front 42

Auditory cortical areas are found in

Back 42

superior surface of the temporal lobes.