Lecture 35 - Vestibular system Flashcards

1
Q

What is the task of the auditory system?

A

Transduce vibration into electrical activity

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2
Q

What are three sections of the membranous labyrinth?

A

Utricle - Saccule - Semicircular ducts

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3
Q

What is the function of the utricles?

A

Monitor and activate response to linear acceleration of horizontal movements

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4
Q

What is the function of the saccule?

A

Monitor and activate response to linear acceleration of vertical movements

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5
Q

What is the function of the Semicircular ducts?

A

Monitor and respond to angular acceleration of head in all planes

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6
Q

What is the orientation of the semicircular ducts?

A

Anterior - Lateral - Posterior

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7
Q

What neural structure is associated with the vestibular system?

A

Scarpa’s ganglion - vestibular ganglion

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8
Q

What is the electrolyte composition of the perilymph?

A

Increased Na concentration

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9
Q

What is the electrolyte composition of the endolymph?

A

Increased potassium concentration

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10
Q

What are three main structures in an ampulla?

A

Crista - Cupula - Hair cells

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11
Q

What are the three main structures of the hair cells?

A

Stereocilia - Kinocilium - Afferent/Efferent fibers

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12
Q

What fluid are the hair cells sitting in?

A

Endolymph

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13
Q

What happens within the ampulla when the endolymph is moving?

A

Bends cupula, which in turns tilt the stereocilia and kinocilium

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14
Q

What structure contains the ampullas?

A

Semicircular ducts

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15
Q

What structure are the hair cells embedded into?

A

Crista

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16
Q

What are the structures in the otolithic organs?

A

Otolithic membrane, Otoconia, Macula, Striola

17
Q

What are the two otolithic organs?

A

Utricle and saccule

18
Q

What is moved with the head is moved within the otolith organs?

A

Cap of statoconia movies, causing bending of the hair cells

19
Q

What happens in the otolith organs when the sterocilia bend toward the kinocilium?

A

Hair cells depolarize

20
Q

What molecular structure is linked to the depolarization of the hair cells?

A

Tip link

21
Q

What does the tip link do?

A

Opens mechanically gated K+ channels
More voltage gated calcium channels open
Increase glutamate release

22
Q

What happens in the semicircular ducts when the stereocilia are deflected towards kinocilium?

A

Apical K+ channels open
Depolarization of the cell membrane
Calcium channels open
Synaptic vesicles to open

23
Q

What nerve is affected when the hair cells are depolarized?

A

Afferent nerve firing is increased

24
Q

What happens when the stereocilia deflected away from kinocilium?

A

Decreased firing rate

25
Q

What are the four vestibular nuclei?

A

Superior - Inferior - Medial - Lateral

26
Q

What is VOR?

A

Vestibular reflex with the function of keeping the eyes on an object when the head is in motion relative to that object

27
Q

How is the VOR carried out?

A

Contraction of the extra-ocular eye muscles required to keep that image of that object focused on the fovea

28
Q

What happens when there is a lesion on the vestibular portion of the CN VIII, vestibular apparatus, or nuclei?

A

Perception of moving when not

29
Q

What are the components of the spiral organ?

A

Outer hair cells
Inner hairs
Inner hair cell

30
Q

Where is low frequency sound processed?

A

Towards the helicotrema

31
Q

Where is high frequency sound processed?

A

Toward the oval window

32
Q

What scala interacts with the oval window?

A

Vestibuli

33
Q

What scala interacts with the round window?

A

Tympani

34
Q

What is a sound wave?

A

Pressure displaces scala vestibuli which displaces cochlear duct and spiral organ

35
Q

What projects into the tectorial membrane?

A

Stereocilia

36
Q

What nerve goes into the scala tympani?

A

Cochlear nerve through the spiral ganglion

37
Q

How does a hair cell depolarize?

A

Hair cells bend towards the kinocilia
Opens the mechanically gated potassium channels
More Ca2+ voltage gated open
Glutamate released

38
Q

What is auditory information delivered to and processed in?

A

Auditory cortex

39
Q

What are the tasks of the vestibular system?

A

Senses head movements
Maintain visual axes when head is moving
Send motor commands to trunk and limb muscles to maintain balance