Inner Ear Review 1

Question 1

3 parts of the inner ear

Answer 1

internal acoustic canal
semi circular canals
cochlea

Question 2

primary sensory receptor of the hearing system

Answer 2

organ of corti

Question 3

what wall holds the basilar membrane in the scala media?

Answer 3

spiral limbus

Question 4

what is the “bump” on the stria vascularis called?

Answer 4

spiral prominence

Question 5

where is endolymph produced in the inner ear?

Answer 5

marginal cells (stria vascularis) and dark cells (semi circular canals)

Question 6

what is the space between the outer and inner hair cells called?

Answer 6

tunnel of corti

Question 7

LSU on top means?

Answer 7

lateral ampular nerve, superior ampular nerve, and utricle nerve come from the superior vestibular nerve

Question 8

what comes from the inferior vestibular nerve? (PS)

Answer 8

posterior ampullar nerve, main saccular nerv

Question 9

the endolymphatic sac is encased in the __

Answer 9

vestibular aqueduct

Question 10

where does the vestibular aquaduct go to?

Answer 10

dura mater

Question 11

where does the endolymphatic sac leave the inner ear space?

Answer 11

between the utricle and saccule through the vestibular aquaduct

Question 12

what is the perilymphatic duct?

Answer 12

pathway that connects the perilymph in the scala tympani and vestibule to the subarachnoid space

Question 13

supporting cells of the organ of corti

Answer 13

hensen’s cells (next to ohc), claudius’ cells, deiter’s cells (under OHC), outer and inner epithelial pillar cells (make space for the tunnel of corti)

Question 14

what is the name for the roof of the outer hair cells?

Answer 14

reticular lamina

Question 15

What is the endocochlear potential?

Answer 15

the cochlea’s endolymph is positively charged at 80-100 mV

Question 16

the endocochlear potential is highest where on the cochlea?

Answer 16

the basal turn

Question 17

what can negatively affect the endocochlear potential?

Answer 17

lack of blood and oxygen, metabolism, ion transmitter inhibitors diuretics, etc.

Question 18

Where is endocochlear potential located?

Answer 18

Stria vascularis

Question 19

our OHC can fire very quickly because…

Answer 19

the endocochlear potential has a 120 mV difference between the cells and the endolymph (very excitatory environment)

Question 20

what does the cochlear partition consist of?

Answer 20

basilar membrane, tectorial membrane and organ of corti

Question 21

innervation of inner hair cells

Answer 21

more axosomatic afferent/sensory nerve fibers than axoaxonic motor/efferent fibers

Question 22

outer hair cells primary function

Answer 22

mechanically amplify sound (by dancing)

Question 23

what do the sereocilia sit on?

Answer 23

cuticular plate

Question 24

how does the tectorial membrane attach to the organ of corti?

Answer 24

spiral limbus

Question 25

what kind of transducers are the outer hair cells?

Answer 25

mechano-electrical (convert mechanical changes in voltage to length changes)

Question 26

how is the cochlea "nonlinear"?

Answer 26

because it acts as a "filter" for frequencies to make sure only certain parts of the cochlea respond to certain frequencies, and then compresses those signals to fit our dynamic range

Question 27

What causes hair cell damage?

Answer 27

presbycusis (age related; most common), acoustic trauma (hazardous noise), viral infections (measles, mumps, meningitis), autoimmune disorder, ototoxicity, head trauma, other pathologies

Question 28

process of the hair cells turning mechanical energy into a potential change

Answer 28

potassium rushes in through the stereocilia (once they bend from shortest to tallest to open the channels), calcium comes in to the cell through cell wall channels, glutamate is carried out at the bottom of the cell to the CN VIII afferent ganglion

Question 29

What property allows for amplification of the basilar membrane?

Answer 29

motor-like properties (of OHC's)

Question 30

What makes the stereocilia bend more?

Answer 30

change in the length of the cell

Question 31

What are the two labyrinthine systems?

Answer 31

Osseous labyrinth membraneous labyrinth

Question 32

What part of the bony labyrinth is the central part with its lateral walls containing the oval window?

Answer 32

vestibule

Question 33

Two interconnected sacs in the vestibule:

Answer 33

utricle and saccule

Question 34

receptors cotntained here that are sensitive to gravity and linear movements of the head?

Answer 34

utricle and saccule

Question 35

filled with endolymph and consists of connective tissue and epithelium with 5 openings for the semicircular canals and duct connecting to the saccule

Answer 35

utricle

Question 36

The sense organ of the utricle (oval thickened area which fibers of vestibular branch of acoustic nerve terminates, covered in hair cells that respond to movement in the endolymph)

Answer 36

macula utriculi

Question 37

Has openings into the endolymphatic duct and cochlear duct

Answer 37

saccule

Question 38

The sense organ of the saccule

Answer 38

macula sacculi

Question 39

Receptors located in the ampuallae

Answer 39

cristae ampullaris

Question 40

central bony axis of cochlea

Answer 40

modiolus

Question 41

originates at the oval window and is continuous with the vestibule

Answer 41

scala vestibuli

Question 42

terminates at the round window

Answer 42

scala tympani

Question 43

filled with perilymph

Answer 43

scala vestibuli and scala tympani

Question 44

very narrow apex of the cochlea and connects SV to ST

Answer 44

helicotrema

Question 45

between the SV and ST, triangular passageway, roof is Reissner's membrane amd floor is basilar membrane

Answer 45

scala media (cochlear duct)

Question 46

filled with endolymph and terminates at the helicotrema and contains organ of corti

Answer 46

scala media (cochlear duct)

Question 47

consists of a series of canals and cavities within the dense petrous portion of the temporal bone

Answer 47

bony labyrinth

Question 48

forms the central portion of the bony labyrinth and is continuous with the semicircular canals and with the cochlea.

Answer 48

vestibule

Question 49

Ovoid in shape, it measures about 5 mm in its antero-posterior and vertical dimensions and about 3 mm across

Answer 49

vestibule

Question 50

medial wall presents a number of small perforations including the orifice of endolymphatic duct

Answer 50

vestibule

Question 51

medial most portion of the osseous labyrinth & 35 mm in length

Answer 51

cochlea

Question 52

central core or pillar of bone of cochlea

Answer 52

modiolus

Question 53

crystals located in vestibule

Answer 53

otolysts/otoconia

Question 54

Where the posterior and anterior SCC connect

Answer 54

common crus

Question 55

cell bodies of cn 8 that ride around in the spiral of the cochlea,

Answer 55

spiral ganglion

Question 56

blood supply in cochlea, striped, lateral wall of the cochlear duct

Answer 56

stria vascularis (strip of epithelium)

Question 57

primary auditory neurons

Answer 57

spiral ganglion cells

Question 58

spiral ganglion cells located here, a spiral canal at the periphery of the modiolus

Answer 58

Rosenthal's canal

Question 59

thickened connective tissue lateral to the stria vascularis.

Answer 59

spiral ligament

Question 60

thickened region of connective tissue on vestibular lip of osseous spiral lamina

Answer 60

limbus

Question 61

similar to CSF

Answer 61

Perilymph

Question 62

high in K+ and low in Na+

Answer 62

endolymph

Question 63

similar to intracellular fluid & large positive (+140mV) potential across hair cell membranes

Answer 63

endolymph

Question 64

where is CSF produced

Answer 64

choroid plexus in ventricles

Question 65

How many turns are in the cochlea

Answer 65

2 and a half turns (around modiolus)

Question 66

tissues that arches up to give rise to the Tectorial membrane

Answer 66

limbus

Question 67

allow us to hear 0 dB HL and are responsible for first 40-50 dB of hearing. they help to hear soft sounds and can change length in order to help stimulate IHC's

Answer 67

outer hair cells

Question 68

primary efferent connection in the ear

Answer 68

OHC's