Brainscape's Knowledge GenomeTM

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


See full index

Z MD1 neurology > Hearing and ear anatomy > Flashcards

Hearing and ear anatomy Flashcards

1
Q

what are the components of the outer ear

A

auricle, external auditory meatus and tympanic membrane

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

what is the function of the outer ear

A

collection of sound and localising where the sound came from

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

explain the structure of the external auditory meatus

A
  • lateral 1/3 is cartilagenous - medial 2/3 is bony - lined by hairy skin and Cerumen glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the function of the cerumen glands of the ear

A

prevent maceration of skin from water if it is in the canal

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

explain the nerve supply to the outer ear

A
  • posterior and inferior walls are innervated by the vagus - anterior and superior walls are innervated by the auricular temporal nerve (branch of the 3rd division of the trigeminal nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why can people with ear pain also experience tooth pain and vice versa

A

because the auricular temporal nerve (branch of the 3rd division of the trigeminal nerve) supplies both the external acoustic meatus and the temporo-mandibular joint near the teeth

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

what is the convexity of the tympanic membrane

A

concave externally and convex internally

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

what is the function of the tympanic membrane

A

vibrates at the same frequency and an amplitude relative to the sound wave –> transmits this energy into the middle ear and beyond

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

what causes the “bulge” in the tympanic membrane

A

the handle of malleus bone

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

when you shine a light into the ear… where should you see a cone of light

A

in the antero-inferior quadrant of the tympanic membrane

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

what does it mean if you see a cone of light not in the antero-inferior quandrant of the tympanic membrane

A

that the patient has a build up of pressure in the middle that is changing the concavity of the tympanic membrane (problem with the middle ear)

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

where is the middle ear

A

extends from the tympanic membrane to the petrous part of the temporal bone

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

what are the two parts of the middle ear

A

the epitympanic recess the tympanic cavity proper

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

What are the two “communications” of the middle ear

A
  • mastoid air cells - auditory tube
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the function of the epitympanic recess of the middle ear

A

it communicates with the mastoid air cells of the mastoid bone

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

what is the function of the auditory tube

A

allows communication of the middle ear to the atmosphere through the nasopharynx - allows for equalisation of pressure

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

what is the direction of the auditory tube in an adult

A

antero-inferiorly to the nasopharynx

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

what happens if the auditory tube is blocked

A

middle ear cannot equalise and damage may occur to the tympanic membrane. Can have infection in the middle ear

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

what is the consequence of an infection of the middle ear

A

inflammation of the middle ear –> impact the movements of the bones of the inner ear - problem with hearing

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

why is it easier for infants to get middle ear infections

A

because their auditory tubes are more horizontal until the face of the shape changes with age - harder to drain the middle ear - easier for bacteria to migrate up

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

what are grommits?

A

a tube put through the tympanic membrane to release the pressure in the middle ear

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

what is the long term consequence of multiple chronic ear infections during infancy

A

will end up having language development delay

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

what are the three bones of the middle ear

A

malleus incus stapes

24
Q

where are the bones of the middle ear

A

attached laterally to the tympaic membrane (via malleus) and medially to the oval window of the petrous bone (via stapes)

25
Q

what is the function of the bones of the middle ear

A

vibrate to transmit the sound to the nerves –> brain –> sound

26
Q

what are the 2 muscles attached to the bones of the middle ear? What are their innervation? And what are they attached to?

A

stapedius (CNVII) - attached to stapes bone tensory tympani (CNV) - attached to malleus

27
Q

what is the function of the little muscles in the middle ear

A

to dampen down the amplitude of the vibration of the sound when a noise is excessive to prevent damage

28
Q

how do the stapedius and tensor tympani dampen down sound

A

large movement of the inner ear bones causes them to contract and therefore the bones cant vibrate as much –> dampening down the energy taken through to the inner ear

29
Q

name one example of a condition where the muscles in the inner ear are unable to dampen down sound amplitude

A

acoustic neuroma - compresses VII - stapedius unable to contract with loud sound

30
Q

what are the 3 important landmarks of the medial wall of the middle ear

A
  • oval window - stapeus attaches to it - round window - opening of middle ear back out to outer ear - promontary - basal turn of cochlea pressing onto the medial wall
31
Q

what nerve runs through the middle ear

A

chorda tympani (branch of the facial nerve - carrying PNS fibres to the salivary glands and bringing back info about taste)

32
Q

what are the two parts of the cochlea and what is the lymph associated with each called

A

bony labyrinth - perilymph membranous labyrinth - endolymph

33
Q

where is the inner ear

A

within the petrous part of the temporal bone

34
Q

what is the function of the semicircular canals of the inner ear

A

equilibrium, and telling you where your head is (ampulla)

35
Q

what is the membranous labryrinth

A

a closed sac filled with endolymph within the bony labyrinth

36
Q

where are the 3 sites of sensory receptors in the inner ear

A

ampulla - sensory receptors for dynamic equilibrium cochlear duct - sensory receptors for hearing utricle - sensory receptors for static equilibrium

37
Q

what are the equivalents for the following in sound terms: wavelength amplitude waveform

A

wavelength: pitch amplitude: loudness waveform: tone/timbre

38
Q

what is the major function of the ossicles

A

impedence matching - translate the information of the sound wave in air to a sound wave in fluid to the inner ear

39
Q

how does the ear prevent the reflection of the sound wave on water

A

because of the difference in size of the tympanic membrane compared to the oval window –> massive amplification of the signal

40
Q

what are the 3 chambers of the inner ear

A

scala vestibuli scala media scala tympani

41
Q

what are the 3 important components for hearing in the inner ear

A

hair cells basilar membrane tentorial membrane

42
Q

explain the topography of the basilar membrane

A

wider at the apex than at the base base - responds to high frequencies apex - responds to low frequencies

43
Q

where are the hair cells of the ear

A

sandwiched between the basilar membrane and the reticular lamina

44
Q

what is the mechanism for sound collection –> hair cells moving

A

sound –> tentorium vibrates –> ossicles vibrate –> pressure on the oval window –> fluid in inner ear vibrates –> basilar membrane moves in response –> shear force of the tentorial membrane against the hair cells –> neuronal signalling

45
Q

how is a neuronal signal produced

A

movement of the sterocilia towards the kinocilium –> complete opening of the potassium channels –> influx of K+ = depolarisation (if sterocilia move the opposite way –> channels close –> hyperpolarisation)

46
Q

explain the asymmetric mechanoelectrical transduction by hair cells

A

the hair cells tend to want to depolarise rather than hyperpolarise (larger change in voltage with change in position for depolarisation compared to hyperpolarisation)

47
Q

how is the potassium gradient set up for the influx into hair cells

A

sella media has a high K+ conc (endolymph) while sea tympani has a low K+ conc (perilymph)

48
Q

what are the different roles of the inner and outer hair cells

A

inner - neuronal signalling outer - amplify the movements of the basilar membrane b contracting (depolarised) or elongating (hyperpolarised)

49
Q

how can aminoglycosides cause hearing loss

A

cause loss of outer hair cells

50
Q

what is the pathway for hearing

A

ear –> hair cells –> CNVIII –> spiral ganglion –> cochlear nucleus in medulla and superior olive –> lateral lemniscus –> inferior colliculus of midbrain –> medial geniculate nucleus of thalamus –> auditory cortex of the temporal lobe

51
Q

where is information from the two ears integrated

A

in the superior olivary complex

52
Q

what components are in the superior olivary complex

A

lateral superior olive - senses intensity differences medial superior olive - senses time differences trapezoid body

53
Q

how does the brain integrate low frequency sound in the horizontal plane

A

neurons come from both L and R ears Whichever neuron has the biggest signal in the medial superior olive - tells us whether the sound comes from the L or R ear

54
Q

how does the brain integrate high frequency sound in the horizontal plane

A

stimulatory neurons come from both L and R ears to the lateral superior olives Inhibitory neurons project contralaterally across to trapezoid body (bigger stimulatory signal = bigger inhibitory signal) Which ever net excitation is higher = sound coming from that side of the body

55
Q

where is the auditory cortex

A

Heschls gyrus (within the lateral sulcus of the temporal lobe)

Z MD1 neurology (17 decks)

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