Vestibular System Flashcards

1
Q

The vestibular system ____ us in space and tells us whether or not we are ____.

A

Orients

Moving

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

The vestibular system, like the auditory system, is connected to the _____ nerve, or ____ ____ ____.

A

Vestibulocochlear nerve

Cranial nerve VIII

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

How many semicircular canals does the vestibular system have? What are they called, and what is the difference between them?

A

3: superior, posterior, horizontal

Each is in a different orientation

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

What does the ampullae contain and what is it attached to? In regards to the ampullae, what is the function of the semicircular canals?

A

Hair cells of semicircular canals, attached to semicircular canals
Semicircular canals provides greater space for endolymph to circulate in order to cause bending of hair cells in ampullae

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

What are the names of the 2 otolith organs of the vestibular system?

A

Saccule

Utricle

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

Yaw rotation corresponds to what type of movement and mostly activates what semicircular canal?

A

Spinning around

Horizontal

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

Pitch rotation corresponds to what type of movement and mostly activates what semicircular canal?

A

Tilting head front or back

Superior canal

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

Roll rotation corresponds to what type of movement and mostly activates what semicircular canal?

A

Tilting head left or right

Posterior canal

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

In the ampulla, the hair cells are in the (same/different) orientation as one another.

A

Same

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

In the otolith organs, the ____ divides them down the center. On either side of the division, the hair cells are oriented in the (same/opposite) directions as those across the division.

A

Striola

Opposite

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

Because the hair cells of the otolith organs are oriented in opposite directions across the striola, some hair cells are ____ with a particular type of movement while others are ____.

A

Excited

Inhibited

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

How is hair cell orientation of the utricle different from the saccule with regards to the striola?

A

Utricle: long stereocilia are oriented towards striola
Saccule: long stereocilia are oriented away from striola

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

All hair cells on one side of the striola will have the same orientation of ____ to _____.

A

Longest

Shortest

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

On top of the hair cells in the otolith organs is a gelatinous _____ layer topped with _____, which are essentially ____ ____ crystals. How does this layer affect hair cell bending upon head bending?

A

Endolymph
Otoconia
Calcium carbonate
Layer applies weight that causes bending of all hair cells in otolith organs upon bending of head and keeps them bent for duration of head bending

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

Hair cells of otolith organs: head is tilted forward, hair cell is (excited/inhibited) and (returns to baseline before head is erected/ remains excited as long as head is tilted). When does the hair cell return to baseline? What happens to the hair cell when the head is tilted backwards?

A

Excited
Remains excited as long as head is tilted
Returns to baseline when head is no longer tilted
Hair cell is inhibited when head is tilted backwards

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

Hair cells of otolith organs: forward acceleration mimics turning head (forward/backward). Does deceleration activate or inhibit hair cells?

A

Backward

Inhibit

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

Each ampule has a grouping of hair cells in the (same/different) basic orientation. Are all the hair cells excited or inhibited by the same movement, or are only some?

A

Same

All are excited or inhibited by same movement

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

In the ampula, sloshing of ____ on one side causes ____ on the other side to move, bending the hair cells towards the (shortest/longest).

A

Endolymph
Fluid
Longest

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

The otolith organs sense ___ ___ and ___ acceleration.

A

Head tilt

Linear acceleration

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

In the otolith organs, a hair cell that is excited by forward tilt is (excited/inhibited) by backward tilt. A hair cell on the other side of the striola from the first hair cell would be (excited/inhibited) by forward tilt and (excited/inhibited) by backward tilt.

A

Inhibited
Inhibited
Excited

21
Q

A ____ compartmentalizes the ampula and the semicircular canals so that sloshing of _____ on one side causes sloshing of the same fluid on the other side.

A

Membrane

Endolymph

22
Q

The hair cells of the ampula are excited when bent from (shortest to longest/ longest to shortest) and are inhibited when bent from (shortest to longest/ longest to shortest).

A

Shortest to longest

Longest to shortest

23
Q

The stereocilia of the ampullae respond to (change in head motion/ constant head motion/ both). How is this different from the otolith organs? Why?

A

Change in head motion only
Otolith organs can respond to change in head tilt as well as constant head tilt because the gelatinous endolymph and otoconia respond to gravity, keeping the hair cells bent as long as the head is bent

24
Q

Ampula hair cell firing with acceleration and deceleration: firing peaks when? What happens to firing when velocity is constant? When is the hair cell inhibited?

A

Firing peaks at start of acceleration
Velocity is constant: firing ceases
Inhibited at start of deceleration

25
Q

Semicircular canals sense direction and speed of _____ acceleration.

A

Angular

26
Q

True or false: both the otolith organs and semicircular canals respond to acceleration.

A

True

27
Q

The (otolith organs/ semicircular canals/ neither) respond to constant velocity. The (otolith organs/ semicirulcar canals/ neither) respond to constant head tilt.

A

Neither

Otolith organs

28
Q

The horizontal canals are most activated by shaking head (yes/no). The superior canals are most activated by shaking head (yes/no). The posterior canals are most activated by tilting head ___ or ____ (direction).

A

No
Yes
Left or right

29
Q

When turning the head to one side (left or right), the posterior or horizontal canals (depending on the type of motion) on the (same/opposite) side of motion are activated, whereas the posterior or horizontal canals on the (same/opposite) side of motion are inhibited. For instance, turning the head towards the right shoulder would activate the (left/right) horizontal canal while inhibiting the (left/right) horizontal canal.

A

Same
Opposite
Right
Left

30
Q

The superior canals are most activated when the head is turned (forward/backward) and are most inhibited when the head is turned (forward/backward). The left and right superior canals are activated (at the same time/ at different times). Why?

A

Forward
Backward
At the same time
Moving head forward and backwards doesn’t involve left to right motion, so left and right superior canals are activated at the same time

31
Q

Rotating the body to the left (counterclockwise) while sitting on the center of a merry-go-round: which semicircular canals are activated, and on which side? Which side is inhibited?

A

Horizontal canals

Left is activated, right is inhibited

32
Q

Accelerating in a clockwise circle when driving onto a curved ramp: which semicircular canals are activated, and on which side? Which side is inhibited? Are any other parts of the vestibular system activated? If so, which ones and on which side(s)?

A

Horizontal canals
Right is activated, left is inhibited
Some hair cells in otolith organs are activated on both sides

33
Q

Nodding head forward to answer yes: which semicircular canals are activated, and on which side? Which side is inhibited? What happens when the head is returned to its upright position?

A

Superior canals
Both sides are activated, neither side is inhibited
Superior canals return to baseline

34
Q

The vestibular ocular reflex enables the ____ to readjust when the body is moving, as when walking. Without it, how would the world appear when walking?

A

Eyes

World would appear to bounce up and down

35
Q

Vestibular ocular reflex: In a normal conscious person, a head turn to one direction elicits first a (fast/slow) movement of the eyes to the (new direction/back to the original direction) and then a (fast/slow) movement of the eyes (to realign with the new head position/ refocus on the original focal spot). Which of these two eye movements only occurs when conscious?

A
Slow
Back to the original direction
Fast
Realign with new head position
Second (fast movement of eyes to realign with new head position)
36
Q

Vestibular ocular pathway (part 1): Information from one side of the body comes in through ____ ____ and makes 2 synapses in the ___ ____ ____ of the ____. One neuron crosses to the contralateral side of the brain and is (excitatory/inhibitory) and the other stays on the ipsilateral side of the brain and is (excitatory/inhibitory).

A
Scarpa's ganglion
Medial vestibular nucleus 
Medulla
Excitatory
Inhibitory
37
Q

Vestibular ocular pathway (part 2): the information coming from the two neurons in the ___ ____ ____ is carried to the ____ ____ of the _____ and makes ___ more synapses there, leading to ___ total neurons synapsed upon.

A
Medial vestibular nucleus
Abducens nucleus
Pons
2
4
38
Q

Vestibular ocular pathway (part 3): one neuron synapsed upon by the contralateral (excitatory/inhibitory) neuron in the ___ ___ synapses upon the (contralateral/ipsilateral) eye’s ____ rectus, causing it to (contract/relax). The other neuron synapsed upon crosses over, becoming (contralateral/ipsilateral), then synapses in the _____ ____ and (activates/inhibits) the tract that goes to the (contralateral/ipsilateral) eye’s ___ rectus, causing it to (contract/relax). The result is that the eyes move in the (contralateral/ipsilateral) direction as the head motion.

A
Excitatory
Abducens nucleus
Contralateral
Lateral rectus
Contract
Ipsilateral
Oculomotor nucleus 
Activates
Ipsilateral
Medial rectus
Contract
Contralateral
39
Q

Vestibular ocular pathway (part 3): one neuron synapsed upon by the ipsilateral (excitatory/inhibitory) neuron in the ___ ___ synapses upon the (contralateral/ipsilateral) eye’s ____ rectus, causing it to (contract/relax). The other neuron synapsed upon crosses over, becoming (contralateral/ipsilateral), then synapses in the _____ ____ and (activates/inhibits) the tract that goes to the (contralateral/ipsilateral) eye’s ___ rectus, causing it to (contract/relax). The result is that the eyes are prevented from moving in the (contralateral/ipsilateral) direction as the head motion.

A
Inhibitory
Abducens nucleus
Ipsilateral 
Lateral rectus
Relax
Contralateral
Oculomotor nucleus
Inhibits
Contralateral
Medial rectus
Relax
Ipsilateral
40
Q

Vestibular ocular reflex: when the head is turned left, the ____ horizontal canal is activated. The neuron that projects contralaterally from the medial vestibular nucleus to the abducens nucleus is (excitatory/inhibitory), and activating it causes contraction of the (left/right) lateral rectus and the (left/right) medial rectus. The neuron that projects ipsilaterally from the medial vestibular nucleus to the abducens nucleus is (excitatory/inhibitory), and activating it causes relaxation of the (left/right) lateral rectus and the (left/right) medial rectus. As a result, the eyes turn to the (left/right).

A
Left
Excitatory
Right lateral rectus
Left medial rectus
Inhibitory
Left lateral rectus
Right medial rectus
Right
41
Q

When the medial rectus contracts, it makes the eyes move toward the (periphery/middle). When the lateral rectus contracts, it makes the eyes move towards the (periphery/middle).

A

Middle

Periphery

42
Q

Contraction of the left eye’s medial rectus muscle will move the ___ eye to the ____.

A

Left eye

Right

43
Q

When the head is reclined at a 30 degree angle, the ___ canals are in the same plane as the table and the vestibular ocular reflex can be tested. Putting warm water in the ear mimics turning the head in the (same/opposite) direction as the ear that has the warm water, so the eyes turn to the (same/opposite) direction as the ear. Putting cold water in the ear mimics turning the head in the (same/opposite) direction as the ear that has the cold water, so the eyes turn in the (same/opposite) direction as the ear.

A
Horizontal
Same
Opposite
Opposite
Same
44
Q

In an unconscious person with no brain damage, would the person’s eyes move rapidly back when testing the vestibular ocular reflex with water or would they stay in the same position? Why?

A

Stay in the same position

Fast movement of the eyes to realign with the new head position is disabled when the person is unconscious

45
Q

The ___ ____ ____ is the place in the midbrain is the place where crossing over of neurons occurs for wiring to the medial recti in the vestibular ocular pathway.

A

Medial longitudinal fasciculus

46
Q

Damage at the medial longitudinal fasciculus would affect the functioning of the (medial retcti/lateral recti) of each eye.

A

Medial recti

47
Q

Damage to the medial longitudinal fasciculus: putting cold water in the right ear, which mimics turning the head to the (left/right), would activate the (left/right) horiztonal canal. However, disruption of the signal telling the right medial rectus to (contract/relax) and the left medial rectus to (contract/relax) combined with the intact signals to the lateral recti means that the right eye would move (left/right/not at all) and the left eye would move (right/left/not at all).

A
Left
Left
Relax
Contract
Right
Not at all
48
Q

Damage to the lower brainstem would cause the (ipsilateral/contralateral/both) pathways to be disrupted. What would be the result of putting cold water in the right ear?

A

Both

No movement of eyes

49
Q

When putting warm water into the right ear of a person with medial longitudinal fasciculus damage, only the ___ eye would move to the ____.

A

Left

Left