The Vestibular System Flashcards

1
Q

Where is the vestibular system found?

A

Within the inner ear

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2
Q

Which bone in the skull are the labyrinths embedded ?

A

Temporal bone

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3
Q

The vestibular apparatus consists of what?

A

3 semi-circular canals

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4
Q

What are the vesticular apparatus connected to?

A

Utricle and Saccule

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5
Q

What are the swellings at the base of the semi-circular canals called and what is found there?

A

Ampulla

Cristae and hair cells

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6
Q

The utricle and saccule together are known as the _______

A

Otolith organs

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7
Q

What do the semi-circular canals detect?

A

Rotational acceleration

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8
Q

The utricle detects _______ and _______ movements

A

back and front tilt

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9
Q

The saccule detects _____ movement

A

Vertical

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10
Q

Where are the Cristae found ?

A

In the ampulla (At the swellings at the bottom of the semicircular canals)

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11
Q

What do the cristae consist of?

A

Cupula (Gelatinous substance which suspends the cillia

Cillia (Stereocillia & Kinocillium)

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12
Q

What are the cillia within the cristae directly linked to?

A

They synapse directly with the sensory neurons of the vestibulochoclear nerve

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13
Q

Endolymph does what to the gelatinous capula?

A

Pushes it activating receptor cells

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14
Q

What is the relationship with regards to movement of the cillia and the rotational movement of the head?

A

The cillia and cupula move in the opposite direction from one another at first until inertia is overcome

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15
Q

How does dizziness occur?

A

A sudden stop will caise the endolymph to continue to move due to momentum which creates a sensation of dizziness as the brain thinks you’re still moving

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16
Q

Distortion of the cillia in the direction of the __________ causes depolarisation and increases the discharge of AP’s in the vestibular nerve

A

Kinocillium

17
Q

Distortion away from the _________ leads to hyperpolarisation and decreased discharge of APs in the vestibular nerve

A

Kinocillium

18
Q

The sensory part of the Otolith organs are collectively known as what?

A

Maculae

19
Q

What is the distribution of small and large cillia within the maculae?

A

One large cillia (Kinocilium) and many smaller cillia (Stereo cillia)

20
Q

What is embedded in the otolith membrane in the maculae?

A

CaCO3 crystals known as otoliths

21
Q

What is more affected by gravity endolymph or otolths ?

A

Otoliths, they have a greater density

22
Q

What are the 3 vestibular reflexes?

A

Tonic labyrinthine reflexes
Dynamic righting reflexes
Vestibulo-ocular reflexes

23
Q

What are the tonic labyrinthine reflexes ?

A

Keeps the head in line with the body - utilises neck proprioceptors

24
Q

What are dynamic righting reflexes?

A

Quick postural adjustments that stop you falling when you trip (Profound in cats)

25
Q

What are vestibulo-ocular reflexes?

A

Static reflex when you tilt your head and your eyes adjust to compensate

26
Q

What is dynamic vestibular nystagmus?

A

A series of eye movements that rotate the eye in the direction of rotation so that gaze is preserved.

27
Q

How can vestibular nystagmus be used to test vestibular function?

A

Post-rotatory nystagmus -Rotated in a chair
Caloric stimulation - Water temperatures can cause convection currents which affect endolymph. Warm water affects the same side and cold water affects the opposite side (COWS acronym)

28
Q

What is Labyrinthitis?

A

Acute interference with vestibular function as a result of infection (Vertigo)

29
Q

What is vertigo?

A

Perception of movement in the absence of movement

30
Q

What is menieres disease?

A
Vertigo
Nausea
Nystagmus
Tinnitus
Associated with overproduction of endolymph which causes an increase in pressure