Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHGY 209 > CNS/sensory 5 - auditory > Flashcards

CNS/sensory 5 - auditory Flashcards

1
Q

describe amplitude and frequency of sound

A

changes of pressure around head
auditory system detects changes in pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are hertz

A

number of cycles per second = frequency = pitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is amplitude

A

Loudness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe normal audibility curve

A

dB = 20log (sound pressure/reference pressure
20 change in db = 10 times louder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

descrive frequency range of humans

A

~10khz
to 20 khz
human voice = 1-4khz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is damage threshold

A

less than pain threshold
not just loudness but duration
Around 80db

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is presbycusis

A

adavancing age = loss of hearing at high frequencies (>1000hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is external auditory cannal

A

pinna reflects pressure wave into it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is pinna

A

folds = reflect certain frequencies of sounds into external auditory canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is middle ear

A

has 3 smallest bones in body
malleus, incus, stapes
connects tympanic membrane to another membrane on other side of ear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is inner ear

A

in skull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is cochlea

A

shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is eustachian tube

A

middle ear attached to back of throat through this
can hear in airplane - open mouth and equalize pressure in middle ear, also when have cold = inflammation and cannot regulate pressure well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is tympanic membrane

A

strike eardrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is semicircular canals

A

loops of vestibular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is oval window

A

flexible membrane that transmits sound in ear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is round window

A

another membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is sensory epithelia

A

where afferent are for cochlea = perception of sound waves occurs, transduction and vestibular organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is utricle and saccule

A

vestibular organs
encodes horizontal and vertical acceleration of head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

name vestibular organs

A

5 of them = 3 semicircular canals, utricle, saccule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe flow of sound energy - beginning

A

tympanum = pushed by pressure waves
amplification modulated by skeletal muscles
linked to oval window by 3 bones = malleus, incus, stapes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what happens to tympanum when pressure

A

pressure decrease= eardrum pulled out
pressure increase=eardrum pushed in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe amplification modulated by skeletal muscles

A

mechanical coupling of tiny bones innervated by skeletal muscles
contract when loud noise since limited range in which they can move = contract before sound to reduce amount of movement
if do not expect sound = will not contract and do job
large eardrum but small oval window = so force amplified, behind window = fluid

24
Q

describe flow of sound energy - end

A

oval window = flexible membrane, pushed in or out, pressure waves go to flui
scala vestibuli = attached to oval window and pushes pressure waves down cochlea, fluid filled compartment
then comes back down
scala tympani
basilar membrane = vibrates up and down in response to pressure waves in compartments, mechanical properties of basilar membrane not uniform across cochlea
oval window pushes in = pushes out round window which moves back and forth
cochlear duct = scala media - in between 2 other scala

25
Q

motion of basilar membrane is

A

Frequency dependent
locations of vibrations are a function of frequency of sound

26
Q

describe where frequencies fall on basilar membrane

A

low frequencies = towards tip of cochlea
as frequencies increase = vibrations move closer to oval and round window
complex sounds = vibrations in multiple locations

27
Q

what does basilar membrane encode

A

frequency of sound in location dependent manner

28
Q

where is basilar membrane motion converted into neuronal activity

A

organ of corti
on top of basilar membrane = where afferent located

29
Q

what does deflection of basilar membrane produce

A

shearing of hair cell stereocilia

30
Q

describe organ of corti

A

4 rows of specialized hair cells down cochlea
hair on apical surfaces

31
Q

describe inner hair cells

A

1 row
where afferents and transduction from
afferent synapse onto hair cells = release neurotransmitter and sends info to brain

32
Q

describe what happens as basilar membrane moves to the stereocilia

A

stereocilia moves (activated to tectorial membrane)
bend or pulled in ways = move back and forth

33
Q

describe outer hair cells

A

some afferents come from 3 outer rows of hair cells
but really receive afferents

34
Q

describe outer hair cell electromotility

A

shorten when depolarized
lengthened when hyperpolarized
hair cell electromobility augments basilar membrane motion
alter how basilar membrane vibrates = allows cns to focus on certain properties by activating outer hair cells

35
Q

describe clinical implications of outer hair cell electromotility

A

otoacoustic emissions = reflex, are used to evaluate hearing in newborns
outer hair cells make noise, do not hear them tho, makes click and can hear with microphone
way to test functioning = play click and wait for it to come back, if dont hear click = outer hair cells not doing what they should
hearing is important for language development

36
Q

what do hair cells contain

A

mechanoreceptors
bend stereocilia

37
Q

describe bending of stereocilia

A

Distance between ends of stereocilia are getting small as they are pushed or bent = clue as to where ion channels are

38
Q

what connects stereocilia

A

tip links = tiny molecular threads attaching them

39
Q

describe tip links

A

coated tip links between stereocilia
~15000 hair cells/inner hair cells in reach row = where transduction occurs
do not have many hair cells in cochlea
~10-20 stereocilia and one tip link per cell = ~100000 or 200000 tip links per cochlea
When break = problem

40
Q

where are ion channels on cilia

A

on each side of tip link
as they move = tip link string pulls open channels when stereocilia move further apart
when move closer togetehr = tip links relax = less tension to ion channels close

41
Q

what do tip links do

A

gate ion channels in stereocilia
each side ot tip link between taller and shorter stereocilia
pulls ion channel and lets potassium through = transduction

42
Q

what does mechano transduction at tip link activate

A

afferent neurons

43
Q

describe mechanotransduction at tip link

A

move in direction of tallest stereocilia = open
move in other direction = close

44
Q

describe moving in direction of tallest stereocilia

A

k+ comes in and depolarizes cell and causes influx of calcium and neurotransmitter released on afferent and send ap to brain

45
Q

why does potassium cause depolarization

A

fluid in cochlear duct is different from other fluids = it has high potassium, usually low potassium in ecf and high in cells but opposite in cochlear duct

46
Q

what is tinnitus

A

ringing in ears
permanent
does not stop

47
Q

name 2 types of tinnitus

A

transient
chronic

48
Q

describe transient tinnitus

A

less and 24 hrs
usually due to loud noise
excessive mechanical stress of stereocilia
tip links are though to break but eventually grow back = ringing stops

49
Q

describe chronic tinnitus

A

many causes but mostly loud noise
origin can be either inner ear, nerve or central pathways
Impacts quality of life - does not stop
mechanical damage or if damage to central auditory pathways

50
Q

compare visual and auditory transduction - visual

A

photons = high energy but hard to catch, ~100x10^6 photoreceptors
trillions of opsin molecules
slow = g protein cascade
amplification closes many ion channels

51
Q

compare visual and auditory transduction - auditory

A

sound waves = low energy but all around ~15000 hair cells, easy to catch but low energy
Several hundred thousand tip links
fast = direct channel activation
no amplification of transduction (yes mechanical but not of transduction)

52
Q

describe cochlear implant

A

hair cell loss due to aging, loud sounds, ototoxic drugs
reestablish hearing in deaf

53
Q

describe process of cochlear implant

A

implanted through round window
electrode place in scala tympani
Electrodes are spaced along the cochlear spiral to stimulate groups of afferent fibers that respond to different frequencies ~12 electrodes
sounds a bit diff but does work

54
Q

what is deafness usually due to

A

transduction process does not work but afferents still there
so cochlear implants take sound through microphone and transmit through electrodes –> stimulates afferents and fire aps
decomposes frequency of sounds and stimulates right electrode in right location = figure out what frequencies are in sound= what basilar membrane does

55
Q

describe central auditory pathways

A

8th cranial nerve - vestibular and auditory
enters brainstem at level of medulla
bilaterally represented across midline = ipsilateral and contralateral at same time
Thalamus
primary auditory cortex = recieves input from both ears

56
Q

why is it important that receive info from both ears

A

use differences between sounds that being sent from each ear to do sound localization

57
Q

name 3 steps to locating source

A

1 - time it takes sound to enter and activate cochlea on both sides (sound on left hits right cochlea later, microseconds but neurons are sensitive to it)
2 - head blocks pressure waves so amplitude depends on how its coming towards you
3 - pinna (ear) reflects sound coming in diff directions and also helps determine ability to locate sound
neurons use slight differences to help determine where sound is coming from

PHGY 209 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions