Chapter 11: Inner ear

What may explain why Outer hair cells are motile?

Actin

If two different frequencies are received by the cochlea at the same time, they will create ______________ ___________ at different areas on the basilar membrane

maximum displacement

Shearing of stereocilia causes what to occur?

mechanical energy transduced into electrochemical energy

The osseous spiral lamina projects from the _______________

modiolus

The central axis of the cochlea is called the ________________ acting as the ____________ wall

modiolus, inner

outer hair cell expanding and contracting is known as the hair cell's ________________ and are changes in _______________ (width/length)

motility, length

The cochlea is ____________ shaped

snail

What must occur in order for haircells to transduce stereocilia?

the permeability of the haircfell mebrane must become semipermeable so ions can flow in and out

How are vibrations able to reach the inner ear?

the stapes

What fluid fills the scala media? What fluid fills the scala tympani and scala vestibuli? What fluid fills the tunnel created by the rods of Corti?

1) endolymph 2)perilymph 3Cortilymph

Each cell contains how many stereocillia? What kind of pattern are they arranged in and how many rows are on each cell?

150 V or W pattern 3-4 rows

The cochlea is coiled __________ turns

2-5/8

The OHC's are supported by how many cells? What are their names?

3 Claudius Hensen Deiters

How many canals make up the semicircular canals? What are their names?

3 Superior Posterior Lateral

The cochlea has ____________ scala, their names are...........???

3 scala vestibuli, scala media, scala tympani

How many stereocillia do inner hair cells have, how many rows are they arranged in, and what is their configuration?

40 1-2 rows single line configuration

How much does the Cochlear amplifier contribute to our hearing?

40 dB

The cochlear duct is bound by what structures?

Basilar membrane from below, Reissner's membrane from above, stia vascularis from the side

Vibrations in the cochlea eventually get translated into? A. sound waves B. Cochlear amplifications C. Nerve information D. acoustical energy information E. Reflexive action

C.

The outer hair cells help provide a ________________ _____________________ for the transduction of small vibrations into neural impulses explaining why our ears are so sensitive

Cochlear Amplifier

Hair cells are the ___________________ ________________ of the auditory system A. biological land mines B. Biological inibitors C. Biological transmitters D. Biological transducers E. Biological translators

D

T or F: Only Outer Hair cells have stereocillia

False: Inner hair cells have them only they do not have any that are embedded in the tectorial membrane

T or F: Hair cells cause bio mechanical action to occur that travel through the auditory nervous system

False: bioelectric

T or F: The inner hair cells have width motility

False: not motile

T or F: The tallest row of cilia are embedded in the basilar membrane

False: tectorial membrane

What does BM displacement tell us

Frequency, intensity, and temporal patteren

Endolymph is high in ________________ (K/Na) and low in _______________(K/Na)

K, Na

Perilymph is high in _______________ (K/Na) and low in __________(K/Na)

Na, K

OHC = ?????? IHC = ??????

Outer hair cell inner hair cell

What are the two walls of the scala media that give rise to the other two scala?

Reissner's membrane Basilar membrane

What are the three parts of the inner ear?

Semicircular canals Vestibule Cochlea

Explain why higher frequencies are stimulated at the base of the cochlea while lower frequencies are stimulated at the apex.

The cochlea is tonotopically organized The BM becomes wider and more flacdid as it gets closer to the helicotrema thus why lower frequencies are stimulated at the top and why higher ones are stimulated at the smaller, more tense section of the BM.

What allows for the Cochlear amplifier to work the way it does in boosting our hearing?

The motility of the hair cells

What is the general function of the cochlea and the basilar membrane?

To translate mechanical energy into nerve information

T or F: Stereocilia are linked together by cross bridges

True

T or F: The tectorial membrane and basilar membrane move differently

True

T or F: the base of the cochlea can respond to high and low frequency stimulation

True

Where is the cochlea wider and more flaccid? Where is it thinner and more tense?

Wider and more flaccid toward the apex and its thinner and tenser at the base.

The structures within the vestibular system are responsible for our ___________________ and allows us to detect ______________ and _________________

balance, motion, direction

Traveling waves go from the _____________ to the _____________ in the cochlea

base to Apex

The vibration of the fluids in the cochlea causes the ________________ to move , causing the cillia of the hair cells to __________________

basilar membrane, bend

What is meant by the term "biomechanics"

cell work

What is the primary audiory organ of the inner ear?

cochlea

What's a synonym for the scala media?

cochlear duct

Why are stereocilia important?

crucial in transducing movement into chemical events that lead to neural transmission

The cochlea resembles a tube of _______________(decreasing/increasing) diameter where it ______________(begins/terminates) at the apex and _______________(begins/terminates) at the base.

decreasing, terminates, begins

What is the stria vascularis made up of?

dense layer of blood capilaries and specialized cell

The inner hair cells act as the sound ______________ while the outer hair cells act as the the sound ______________

detectors, amplifiers

The greater the stimulus level the greater amount of BM _____________

displacement

The round window __________________ the pressure of the traveling wave along the _____________ membrane

equalizes, basilar

Where are the Inner Hair cells located?

inner side of the inner rods

The organ of corti is divided into and ____________ and ___________ portion

inner, outer

What are the types of hair cells?

inner, outer

What happens when an outer hair cell is stimulated?

it expands and contracts

What is the name for the tallest stereocilia?

kinocilium

The apical end of the BM vibrates only to ____________ frequency stimulation

low

Where are the structures of the inner ear located?

on the temporal bone

What is the thin boney shelf that divides cochlea throughout its length?

osseous spiral lamina

What kind of drugs damage hair cells and cause a Sensorineural loss?

ototoxic drugs

Where are the outer hair cells located?

outer side of the outer rods

The scala vestibuli extends from the ________________ ______________ where the stapes footplate sits and pivots or rocks in and out of

oval window

The organ of corti is divided into an outer and inner portion by the _______________ or _____________ of Corti

pillars , rods

When the basialr and tectorial membranes are displaced, they ________________ about the 2 hinge points causing __________________ forces to occur

pivot, shearing

The scala tympani leads up to the ______________ _________________

round window

Where is the Organ of Corti located?

scala media, basilar membrane

When the outer hair cells are damaged what is lost?

sensitivity, frequency resolution

What is the general shape of an inner hair cell?

spindle or vase

The Tectorial membrane is hinged to the _____________ _______________ and the Basilar membrane is hinged to the ________________ _______________ ______________

spiral limbus, osseous spiral lamina

What structures trigger the neuronal response to send the signal up the auditory pathway?

sterocillia

What is the function of the cross bridges/tip lengths of the stereocilia?

strengthen the cilia and allow them to move together and not independently

The outer wall of the scala media is covered by the ______________ ___________________

stria vascularis

What provides blood to the cochlea?

stria vascularis

What structure that has stereocillia embedded in it vibrates when the basilar membrane vibrates?

tectorial membrane

Outer hair cells are what kind of shape?

test tube

Nerve potentials are initiated by .......................?

the bending of the cilia

Why is the function of the rocking and pivoting motion of the stapes footplate?

to transmit sound waves through the cochlea

Shearing is when _______________ (top/bottom) moves more than the ____________(top/bottom)

top, bottom

Where is there greater displacement in the basilar membrane?

toward the apical portion

The vibratory patterns of the basilar membrane are referred to as a ________________ ________________

traveling wave

For a traveling wave one part of the BM may be displaced toward the scala ___________while the adjacent part will be deflected toward the scala ___________

tympani, media

The vestibule houses the _____________ and ________________

utricle, saccule

All of the semicircular canals open up into the _____________

vestibule

The cochlear fluid ______________ as sound is transferred through the oval window

vibrates