W1D1 - Neuro - Auditory And Vestibular System

Front 1

The structures innervated by the 8th cranial nerve are embedded in the

Back 1

hardest bone int he body - the petrous (like a rock) portion of the temporal bone.

Front 2

because the tube consists of so many twists and turn it is called the

Back 2

bony labyrinth

Front 3

The coiled ________- extends anteriorly from an enlargement called the vestibule, to which three semicircular cnals are attached

Back 3

cochlea

Front 4

The membranous labyrinth, the membranous tube suspended within the bony labyrinth, generally follows the same contours. T/F

Back 4

true

Front 5

There is a ______ duct within the bony cochlea and a _____ duct within each semicircular canal.

Back 5

cochlear, semicircular duct

Front 6

Within the vestibule there are two enlargements.
_____ (to which the semicircular ducts attach)
______ (which is connected to the cochlear duct and to the utricle)

Back 6

utricle and saccule

Front 7

The bony labyrinth is filled with _____lymph, whihc is similar in composition to CSF and therefore to extracelular fluid generally.

Back 7

peri

Front 8

T/F the subarachnoid space around the brain is actually continouous with the perilymphatic space of the bony labyrinth through a tiny canal in the temporal bone.

Back 8

true, the cochlear aqueduct.

Front 9

The membranous labyrinth, in contrast is filled with ___lymph, a very peculiar fluid that is more like intracellular fluids in ionic composition.

Back 9

endo

Front 10

T/F the membranous labyrinth is a continuous, closed system in which every part communicated with every other part.

Back 10

true

Front 11

What structures compirse the OUTER ear?

Back 11

auricle and external auditory meatus

Front 12

What is the purpose of the outer ear?

Back 12

conducts sound waves to the tympanic membrane (each nook and crannie acts to distort the sound)- acts as a funnel for sound localization
has hair and cerumen (wax) - to 'catch critters'

Front 13

What are the ossicles?

Back 13

bones of the middle ear
malleus, incus, and stapes

Front 14

What structures comprise the middle ear? Where are they located?

Back 14

located in petrous part of temporal bone
osseus labyrinth and mem. labyrinth
ossicles
stapedius
tensor tympani
tympanic membrane

Front 15

What is the purpose/function of the middle ear?

Back 15

amplifier and impedance matching device
communicates with nasophayrnx via auditory tube
sensory innervation from IX
Pathology = conduction deafness
Stapedius - connects to stapes, innervated by CN VII
Tensory Tympani - connects to malleus, innervated by CN V

Front 16

How does the middle ear communicate with the nasopharynx?

Back 16

auditory tube

Front 17

What is the stapeduis connected to and what is it innervated by?

Back 17

CN VII - connected to stapes

Front 18

What is the tensor tympani connected to and what innervates it?

Back 18

connects to malleus, innervated by CN V

Front 19

What structure is 15x bigger than a the oval window?

Back 19

tympanic membrane

Front 20

What structures convey 60% fidelity into coiled cochlea?

Back 20

oval window

Front 21

What is the purpose of the auditory tube?

Back 21

air-filled cavity - connects to nasopharynx - pressure equalizer

Front 22

What structure in th emiddle ear is normally coiled tightly 2 and 3/4 times?

Back 22

cochlea

Front 23

What membrane is found within the coiled cochlea?

Back 23

Reissner's Membrane

Front 24

What ossicle is attached at the oval window?

Back 24

stapes

Front 25

What is the round window?

Back 25

structure found below oval window that helps with the pressure from the fluid recieving vibrations

Front 26

What sensory innervation does the middle ear receive?

Back 26

from IX - glossopharyngeal

Front 27

The semicircular ducts communicate with the ____-, while the cochlear duct communicates with the _____-

Back 27

utricle, saccule

Front 28

What structure is found within the inner ear?

Back 28

osseus labyrinth - the coiled cochlea - located in bony labyrinth of temporal bone

Front 29

What 'scala' are found within the cochlea?

Back 29

Scala vestibuli: contains PERIlymph - transmits waves towards the helicotrema
Scala Media (cochlear duct): contains endolymph, contains organ of corti

Front 30

What is the modiolus?

Back 30

The structure that the coiled cochlea is wrapped around - where spiral ganglion are found

Front 31

T/F the spiral ganglion mirror the shape of the modiolus

Back 31

true, the spiral ganglion come out of the cochlear division of CN VIII

Front 32

What is scala tympani?

Back 32

the space within the cochlear found below the cochlear duct - also contains perilymph

Front 33

Where are hair cells found?

Back 33

in the cochlear duct within the organ of corti they are attached to the basilar membrane - "business mem. - very impt.

Front 34

What comprises the organ of Corti?

Back 34

Hair cells, basilar membrane tectorial membrane, spiral ganglion, modiolus of cochlea

Front 35

What type of receptors are hair cells?

Back 35

mechanoreceptors - innervated by cells of the spiral ganglion - primary afferents of choclear nerve.

Front 36

What are hair cells embedded into?

Back 36

tectorial membrane - ONLY OUTER HAIR CELLS are touching tectorial mem. inner DO NOT - which have the majority of the fibrs in CN VIII (vestibulocochlear nerve)

Front 37

T/F 95% of primary afferents come from INNER hair cells

Back 37

true

Front 38

T/F Outer hair cells outnumber inner hair cells - likely pull on the tectorial membrane to fine tune and enhance vibration.

Back 38

true

Front 39

T/F the tectorial membrane is gelatinous

Back 39

treu

Front 40

Where is endolymph being produced?

Back 40

stria vascularis - along the side wall of the scala media - cochlear duct

Front 41

The basilar membrane is ____- and _______ at the base and _- and _______ at the apex(towards the top of the spiral of the cochlear duct)

Back 41

thick and narrow
thin and wide

Front 42

The specific dimensions of the basilar membrane assist in what with sound?

Back 42

everything has a specific vibration "frequency" - part of the basilar membrane will vibrate and the hair cell at that location will send signal = hear sound.

Front 43

What type of frequencies are the base? what about at the apex?

Back 43

base: high frequency bivrations/sounds
apex: low frequency vibrations/sounds

Front 44

T/F the tonotopic organization of the basilar membrane is maintained ALL the way to the cortex

Back 44

true

Front 45

Where does fine tuning of hearing occur?

Back 45

via endolymph flowing past hair cells

Front 46

What is the intesity of a sound dicated by?

Back 46

deteremined by amt. of vibration of basilar membrane and therefore number of hair cells vibrating

Front 47

What is the path taken from the auditory system to the auditory cortex?

Back 47

auditory system -> cochlear nuclei (medulla) -> 2 places: superior olivary nuclues ipsilateral and superior olivary nucleus contralateral via the trapezoid body - MOST of them cross to the contralateral side - some bypass and move through the lat. lemniscus to the inf. colliculs -> from sup. olivary nucleus -> inf. colliculus (part of tectospinal) -> medial geniculate -> auditory cortex, area 42, lat. lobe.

Front 48

What is the feedback pathway that activates the stapedius and dampens osund?

Back 48

after the information crosses via the trapezoid body to the superior olivary nucleus it could be sent to the facial motor nucleus (VII) and then be sent to the stapedius -> dampen sound - although, doesn't prevent damage, may screen out background noise.

Front 49

To be deaf you have to damage what structure?

Back 49

Before trapezoid body

Front 50

T/F Bilateral at ALL levels above cochlear nucles

Back 50

true

Front 51

What contracts when somone slaps you in the face?

Back 51

tensor tympani - we don't know why this happens. - 2 tiny tensors, trigeminal (V) - the tensors are attached to malleus and pulls on that.

Front 52

Nerve Deafness - acheived when _ is damaged. (list all structures that could possibly lead to deafness in an ear)

Back 52

organ of Corti
coclear nuclei
- lead to deafness on one side

Front 53

Brainstem lesions in auditory pathway leads to what?

Back 53

partial loss only due to both crossed and uncrossed fibers in the lateral lemniscus

Front 54

Cortical lesions - lead to?

Back 54

sensory of receptive aphasia and loss of dirction of sound.

Front 55

What are the 3 qualities fo what we hear?

Back 55

Frequency
Location
Intensity

Front 56

What determines the frequency we hear?

Back 56

determined by area of maximum vibration along basilar membrane

Front 57

What determines the Location of what we hear?

Back 57

determined by which ear sound reaches first - by auricle - funnel of ear

Front 58

What determines the intensity of what we hear?

Back 58

by amt. of vibration of basilar mem. and therefore number of hair cells vibrating.

Front 59

What are the organs of static equilibrium?

Back 59

the urticle and saccule

Front 60

Each organ of static equilibrium containts a small patch of hair cell that are what type of receptors?

Back 60

mechano - also supporting cells that make up the macula are present

Front 61

When the head is upright the hair cells of the macula in the utricle project ___, while the hair cells fo the macula in the saccule project _____.

Back 61

utricle - vertically
saccule - horizontally

Front 62

The hair cells are in contact with a sheet of gelatinous material called the ?

Back 62

otolithic mem.

Front 63

What is present on the otolithic mem. that adds weight to the mem. thus making it more sensitive to slight changes in position?

Back 63

otoliths

Front 64

What type of lymph is present within the membranous labrynth where the otoliths and otolithic membrane is found?

Back 64

endo

Front 65

What are the organs of dynamic equilibrium?

Back 65

semicircular canals

Front 66

At the end of each of the three semicircular canals are expanded chambers called?

Back 66

ampulla

Front 67

Each ampulla contains a sm. patch of hair cells (mechanoreceptors) and supporting cells that make up a ___

Back 67

macula

Front 68

There are 3 semilcircular canals that lay at right angles of eachother -

Back 68

superior
posterior
lateral

Front 69

Each ampula contains a crista ampullaris, what is this?

Back 69

composed of hair cells and supporting cells, the hair cells extend into a gelatinous mass called the cupula

Front 70

What structure do the hair cells found in the ampulla innervate?

Back 70

cupula

Front 71

What lymph is assoiated with the crista ampullaris/

Back 71

endo

Front 72

The primary afferent neuron's projections form the vesitbulocochlear nerve, their cell bodies are found in the _________ ganglion (from the hair cells fo the utricle, saccule, and semicircular canals0

Back 72

vestibular ganglion

Front 73

Primary afferents project to the

Back 73

vestibular nuclei, which are found in the medulla, pons, and flocculonodular lobe of the cerebellum

Front 74

Where do the vestibular nuclei project to?

Back 74

cerebellum
spinal cord
motor nucleo of III, IV, and VI
thalamus
contralateral vestibular nuclei
reticular formation
feedback from VIII to labyrint

Front 75

When the endolymph moves in such a way to move the hair cells twoard the kinocillium, what message is sent?

Back 75

stimulation, depolarization - activated

Front 76

T/F at the resting state there is a constant message being sent.

Back 76

true, so that when the lymp flows so that the hair cells move away form the kinocilium inhibition occurs.

Front 77

What type of mvt. is considered static equilibrium?

Back 77

non-rotational mvt. of acceleration

Front 78

Where is scarpa's ganglion and what is it associated with?

Back 78

the ganglion of the hair cells found in the crista ampullaris of CN VIII

Front 79

What is the static labyrinth senstive to?

Back 79

sensitive to "vibrations" from 0-1 Hz
linear acceleration
*Gravity is a form of linear acceleration
Serves as a plumb bob-like reference for the head - uses gravity

Front 80

What is the dynamic equilibrium most sensitive to?

Back 80

cnalas are sensitive to vibrations from 1-10 Hz
specifically respond to angular acceleration
angular acceleration is experienced during trunign mvts. fo the head
The primary function of the dynamic labyrinth is to provide relfex control of eye mvts.

ednolymph in the cnalas does not move when the head is at rest, whe the head truns, the endolymph tend to remain stationary
the cupula of the crista ampullaris deflects when the head urns
the afferent fibers fire, signaling that the head is turning - endolymph lags behind - inertia

Front 81

T/F R and L sides act opposingly, when one side is excited the other is inhibited - they are antagonistic.

Back 81

true

Front 82

What is the Vestibulo-Ocular Reflex?

Back 82

While one side is intiating, the contralateral side is inhibiting the same pathway on it's side - The labyrinth is activated -> Vestibular nuclei -> ipsilateral abducens )-> 2 places: contralateral MLF and ipsilateral lateral rectus of the eye and pulls the eye to the R..while the MLF sends message to oculomotor nucleus -> medial rectus and pulls the L eye to the R as well - "yolks the eyes together.

Front 83

What is Vestibular Nystagmus?

Back 83

involuntary, oscillating eye mvts.
Consists of a slow component opposite the direction of rotation and a fast component in the direction of rotatation.
Always named after the fast, compensatory component
Named after fast "reset" experienced when tracking a moving object or while you're spinning in circles.

Front 84

What test can you use to test the Vestibular nystagmus clinically?

Back 84

caloric test - use warm/cold water
COWS - Cold - Opposite - Warm - Same
will make the eyes go that way

Front 85

What would happen if you had an ear infection?

Back 85

lesion would look like warm water of caloric test - same side nystagmus

Front 86

What would happend i fyoi had a destructive lesion (tumor, vascular, degenerative) -

Back 86

like cold water - opposite nystagmus

Front 87

What would happen if you had a lesion of the cerebellum and/or tracts leading to it (inferior cerebellar peduncle)

Back 87

induces a nystagmus like symptom - Cerebellar nystagmus - due to the loss of coordination of the ocular muscles

Front 88

What would occur if you lesioned III, VI, or nerves of the interconnecting MLF ?

Back 88

abnormal response to caloric test