Brainscape's Knowledge GenomeTM

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


See full index

CNS > Unit 9 - Hearing Anatomy > Flashcards

Unit 9 - Hearing Anatomy Flashcards

1
Q

Auditory system

A

Exteroceptive system concerned with perception of sound

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

Vestibular system

A

Proprioceptive

Concerned with maintenance of equilibrium

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

Where does the vestibulocochlear nerve (CN VIII) emerge

A

SENSORY

Emerges from brainstem at cerebellopontine angle - junction between cerebellum, pons and medulla

Lateral to facial nerve

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

Skull opening that transmits the vestibulocochlear nerve

A

Internal auditory meatus

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

Structures of ear

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

Separation between external and middle ear

A

Tympanic membrane (ear drum)

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

Contents and boundaries of middle ear

A

Air filled space

Bounded by tympanic membrane and inner ear

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

Contents of inner ear/lebyrinth (in petrous portion of temporal bone)

A

Cochlea

Semicircular canals

Vestibule (utricule & saccule)

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

Transmission through outer ear

A

Air pressure fluctuations move tympanic membrane (ear drum) back and forth

Attached to tensor tympani muscle - which it pulls inwards

Cochlea in inner ear conducts sound through fluid instead of air

Before sound passes into inner ear it must be amplified - OSSICLES

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

ossicle bones

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

How do the ossicles amplify sound

A

Stapes rests against cochlea - through oval window

Air pressure pushes on tympanic membrane - vibrates - ossicles move - stapes pushes against cochlea and displaces fluid within SCC and in cochlea to move fibres on hair cells

Tensor tympani muscle attached to malleus

stapedius attached to stapes

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

Tensor tympani muscle attaches to

A

Malleus

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

Stapedius attaches to

A

Stapes

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

Receptors of auditory system

Function

Where are they found

A

Responsible for converting mechanical energy (fluid displacement) into electrochemical energy - travels along cochlear nerve

Hair cells enclosed within inner ear in tubular system are filled with fluid

Auditory hair cells in spiral organ of corti in cochlea

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

What is the cochlea spiral shell composed of

A

3 fluid filled spaces

Scala vestibuli

Scala tympani

Cochlear duct

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

Scala vestibuli & scala tympani

A

Partially enclosed in bone

Bony labyrinth - contains perilymph

continuous with each other

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

Cochlear duct

A

Part of membranous labyrinth (contains endolymph) suspended between bony labyrinth

membranous labyrinth also includes

utricle

saccule

semicircular canals

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

Outer spirals =

pitch of noise

A

= base

Low pitch of noise

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

Centre spirals =

pitch of noise

A

Apex

High pitch of noise

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

Where are the hair cells located

A

Basilar membrane (blue)

21
Q

Oval vs round window

Relationship between movement of stapes and round window

A

Oval window - opens into scala vestibuli

  • Stapes footplate occupies oval window

Round window - opens into scala tympani

  • flexible tympanic membrane at round window

As the stapes moves inward, the round window moves outward

22
Q

What happens when vibrations reach cochlear duct

A

Cochlear duct and basilar membrane are set in motion - hair cells are activated (mechanoreceptor cilia)

23
Q

Categories of auditory hair cells

A

Organ of Corti - 2 hair cell types

Flask shaped inner hair cells

Rectangular shaped outer hair cells

24
Q

Where are stereocilia found

What is the kinocilium in contact with

A

At apical end of each hair cell

Kinocilium located at tallest row of stereocilia

Tips of longest stereocilia in contact with overlying membrane

Basilar membrane moved by fluid movement - stereocilia bend and it changes MP of hair cells

25
Q

Tonotopic representation of hair cells

A

Higher freq sounds activate hair cells near oval window

Lower freq sounds activate hair cells near apex of cochlea

Auditory info tonotopically organised in auditory pathway

26
Q

Spiral shaped cochlea

A

Hair cells are innervated by primary sensory auditory neurons in spiral ganglion

Cell bodies of sensory neurons at spiral ganglion - axons to cochlear nerve

At each of the spirals is the cochlear duct and within that the basilar membrane (with hair cells) - sensory neurons head towards ganglia (collection of cell bodies in same discrete location) - axons converge at the cochlear nerve

27
Q

Pathway of vestibulocochlear nerve (CN VIII)

A
28
Q

Ascending auditory pathways

A

Cochlear nuclei located near inferior cerebellar peduncle

Send fibres medially along trapezoid body to superior olivary nucleus

Fibres ascend bilaterally (mostly on contralateral side) through pons and midbrain

Fibres ascend to nucleus of inferior colliculus or are relayed to thalamus

Eventually terminate in primary auditory cortex

29
Q

How do fibres for auditory pathway travel after the thalamus

A

Fibres pass from thalamus to auditory cortex via auditory radiations

Primary auditory cortex (area 41 & 42) on upper medial surface of superior temporal gyrus (Heschl’s transverse gyri)

Recognition and interpretation of sound on basis of past experience takes place in secondary auditory area

(17 mins - come back to it)

30
Q

Pathway of descending auditory pathways

A

Fibres originate in auditory cortex and nuclei in auditory pathway

Efferent fibres descend to nerve cells at different levels of auditory pathway and hair cells of organ of corti

Nerve fibres act as feedback mechanism to inhibit reception of sound

Auditory sharpening, suppressing some signals and enhancing others

31
Q

Function of vestibular system

A

Maintain equilibrium

Direct gaze of eyes

Preserve constant plane of vision (lead position) by modifying muscle tone

32
Q

Truncal ataxia nerve damage

A

Flocculonodular nerve

33
Q

Structure of cochlea

A
34
Q

Arrangement of semicircular canals

Function

A

Anterior, Posterior and Lateral

Detect angular acceleration around 3 orthogonal axes

Change in motion of head (kinetic) - SCC

Change in position of head with respect to gravity (static) - utricle & saccule (vestibule)

35
Q

What contributes to the feeling weightlessness

A

Canaliths

Move away from hair cells to feel weightless

36
Q

What does each inner ear of vestibular system contain

A

Utricle

Saccule

3 semicircular ducts

37
Q

Contents of utricle and saccule

Function

A

Contain maculae

Cristae - in ampulla of each semicircular duct (head movement)

Head position

38
Q

What is found in the vestibule

A

Hair cells

39
Q

Where are hair cells found

A

Macula of utricle

Macula of saccule

Cristae ampullares of semicircular canals

40
Q

Contents of membranous labyrinths of semicircular canals, utricle and saccule

What is found in each crista

A

Filled with endolymph

Hair cells - stereocilia (75-100) and kinocilium (1) of each hair cell in each crista

41
Q

How are hair cells depolarised/hyperpolarised

A

Each vestibular hair cell is depolarised when sterocilia bend in direction of kinocilium

Hair cell hyperpolarised when deflected in opposite direction

42
Q

Vertigo

A

Imbalance input from right and left sides

43
Q

Layout of macula of saccule & utricle

What amplifies the force of deflection

A

Hair cells embedded in gelatinous matrix

Layers of crystals (otoliths) amplify force caused by deflection of stereocilia

44
Q

Difference between otoliths and cristae

A

Cristae - semicircular canals

Otoliths - in macula of saccule and utricle

45
Q

Utricle & saccule function

A

Changes in position of head with respect to gravity (static)

Detect linear acceleration

Info in relation to sense of gravity

46
Q

Semicircular canals function

A

Changes in motion of head (kinetic)

Detect angular acceleration around 3 orthogonal axes

47
Q

Where do axons of hair cells travel to

A

Ganglia (vestibular)

48
Q

Vestibular pathway

A

Fibres enter anterior surface of brainstem

Nerve fibres divide into short ascending & long descending fibres

TRAVEL TO:

  • cerebellum
  • vestibulospinal tract (head & neck - medial and lateral)
  • vestibulo-ocular reflexes (info in relation to movement of eye - 3rd 4th and 6th - connection to vestibulocochlear nerve)
  • cerebral cortex (specifically primary sensory cortex - behind face, feeling of vertigo)

CNS (36 decks)

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