Brainscape's Knowledge GenomeTM

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


See full index

Neural Control of Human Movement > Topic Test 4 - Part 2 (vestibular) > Flashcards

Topic Test 4 - Part 2 (vestibular) Flashcards

1
Q

describe the vestibular system

A
  • balance, equillibrium, posture
  • based on the motion of hair cells
    >lateral line organs
    >detects movement and vibration in water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe hair cells *

A

we have hairs in ears, most of those detected and that’s how our brain can interpret posture, movement and supports us with balance
- like fish, when the water moves or changes pressure, that causes these hair cells to deflect (but we not in water all the time)

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

humans have a vestibular labyrinth, describe the components

A
  • otolith organs: acceleration and tilt
  • semicircular canals: head rotation
  • both use hair cells to detect changes
  • (info gets sent through a bunch of axons (~20,000 vestibular axons (cell bodies in scarpa’s ganglion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

review, what’s a ganglion?

A

grouping of somas/cell bodies

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

describe the vestibular system mechanics

A
  • acceleration: change in velocity (change in velocity)
  • tilt: orientation of head (we are able to feel tilt from gravity, form of acceleration downward)
  • rotation: more specifically, angular acceleration (spinning that’s happening)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the otolith organs

A

measures acceleration and tilt
- macula: epithelium filled pouch with hair cells
- kinocilium: tallest, most important cilia
- otoconia (ear stones): calcium carbonate crystals

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

what shape are the otolinth organs? *

A

little bean shaped organs

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

tilt is based on _ which is a form of acceleration*

A

gravity

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

describe the kinocilium in more detail

A
  • hair cells in the middle are cilia, the tallest one is the kinocillium
  • important because when the fluid deflexts it will cause the little hair cells to move towards or away from tha big kinocillium (system measures how little hairs move relative to big one)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe how gravity impacts otolinth organs*

A
  • gravity pushes otolinth down, squishing fluid down, but hair cells aren’t deflecting
  • if you tilt your head forward/backward, these stones help to push fluid in one direction
  • tilt head forward = fluid flush backward which will deflext hairs
  • the deflection of hairs is picked up by hair cells and set out from those vestibular axons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how does the speed of APs change depending on the position of hairs around kinocillium?*

A
  • cilia deflect relative to kinocilium
  • have baseline Ps, can increase or decrease that rate
  • hairs bend toward the big hair = speed up
  • bend away = slow down
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe macular orientation

A

array of orientations within organ (rather than only forward/back)
- saccular macula: vertically oriented
- ultricular macula: horizontally oriented
allows measures of all possible linear movements
*bunch of hair cells pointed in different directions, hairs oriented in that direction can identify that deflection

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

describe the semicircular canals

A

measure head rotation (angular acceleration)
- 3 semicircular canals on each side
- help sense all possible head rotation angles

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

describe the components of the semicircular canals

A
  • crista ampullaris: cupula (bubble) full of cilia found within an ampulla (bulge)
  • similar idea to macula, but principle of intertia
  • endolymph reacts slowly to quick rotations which deflects the cupula and cilia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the crista ampullaris*

A
  • instead of having pouches with fluid on top, have pouch of hair with fluid in semi circle, filled with cupula which has cilia in it
  • 3 of them
  • if we turn head, fluid will deflect the bubble in one direction which allows us to measure orientation that occured
    *like sail on boat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

fluid in crista ampullaris measures _ rather than just linear movement

A

rotation

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

describe the semicircular canals in more detail

A
  • each paired on opposite side of head
  • push-pull activation on vestibular axons
  • prolonged rotation will keep fluid in motion (dizziness - opposite direction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what happens at rest in the semicircular canals?

A

at rest, the cupula stands upright

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

what happens during rotational acceleration in the semicircular canals?

A

endolymph moves inside the semicircular canals in the direction opposite the rotation (it lags behind due to inertia)
- endolymph flow bends the cupula and excites the hair cells

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

what happens as rotational movement slows in the semicircular canals?

A

endolymph keeps moving in the direction of the rotation, bending the cupula in the opposite direction from acceleration and inhibiting the hair cells

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

why do we still feel like we are spinning even after we stop?

A

fluid starts to spiral in semicircular canals and when we stop, the fluid is still moving and deflecting hair cells

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

define central vestibular pathways

A

pathways of vestibular information and reflexes to control head, body, eye movement

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

describe the order of central vestibular pathways

A

1) otolith organs + semicircular canals
2) vestibulocochlear nerve (VII)
3) Vestibular nuclei
- dorsolateral regions of medulla
- integrate with other information (visual/motor)
*(all info from sensors in ears going back towards medulla and synapses in the vestibular nucleus)
4) Send out info above and below

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

central vestibular pathways sends information out to

A

1) cerebellum
2) thalamus (ventral posterior nucleus)
3) extraocular motor neurons
4) limbs
5) neck and trunk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

describe the cerebellum step of central vestibular pathways

A

vestibular sensations needed for coordinating movements

26
Q

define the thalamus step of central vestibular pathways

A
  • then projects to post central gyrus
  • info received by the cortex maintains a representation of the body in space
    *info important for representing where our body is in space
27
Q

describe the extraocular motor neurons step in central vestibular pathways

A
  • reflexive eye movements
  • primary goal: maintain gaze
    *if we have head move, need to have reflexive eye movements to maintain gaze
  • can do this because we have the ability to integrate that vestibular info directly to our eyes
28
Q

describe the limbs step of central vestibular pathways

A
  • reflexive limbs movemnets
  • primary goal: keep body upright
29
Q

describe the neck and trunk step of central vestibular pathways

A
  • reflexive neck/trunk movements
  • primary goal: keep head upright
30
Q

why are both the limbs and neck and trunk reflexive movements?

A
  • not sending up to cortex (sending straight down from medulla), will be reflexive movement that happens quick
31
Q

describe the vestibulospinal tract

A
  • origin: vestibular nucleus
  • terminal: spinal cord (to synapse on motor neurons)
32
Q

what’s the function of the vestibulo-ocular reflex

A

to fizate line of sight on visual target during head movement

33
Q

what’s the mechanism of the vestibulo-ocular reflex

A

senses rotation of head, commands compensatory movement of eyes in opposite direction (* eyes reflexively move to correct gaze)

34
Q

what’s a practical application of the vestibulo-ocular system?

A

not hard to see whebn we are running, bobbing up and down
- eyes can automatically adjust vision

35
Q

how do vestibular connections mediate horizontal eye movements?

A
  • excitation of extraocular muscles on one side, inhibition on other side
    *as you turn left eyes need to turn right to maintain gaze, compensate by exciting muscles on right side
  • have semicircular canals on each side, cross over so right will inhibit muscles we don’t want on left and vice versa
36
Q

what are the connections mediating horizontal eye movements?

A

the connections that allow us to keep eye gaze on something
- have semicircular canals that connect to eyes, go through the vestibular nucleus and different oculo-motor nerves on our way to the eyes

37
Q

in the chicken video, we saw that

A

we don’t need magical head control that chikens have cause we have really good vestibulo ocular system

38
Q

what 2 categories of vestibular changes do we see with age

A

peripheral changes and central changes

39
Q

describe the peripheral changes (likely to occur first) with age

A

otolith organs
>loss of cilia
>alterations in otoconia (size and shape)
semicircular canals
>loss of cilia, to a greater extent than otolith organs
>greater impact in VOR and fall risk
*change in sensory organs, not as sensitive to the rotations/tilt, comes from a loss of cilia = less reactive

40
Q

why would peripheral changes contribute to fall risk

A
  • if someone slips and we have greate sensation coming from these semicircular canals, we have quick reflexive movements of our eyes so we can maintain gaze
  • otherwise, lose where our eyes are going and orientation of our head
41
Q

describe the central changes (likely to occur later, after 60 yrs)

A
  • vestibular nuclei - slow loss of neurons
  • cerebellum slow loss or change in connectivity
42
Q

together (both the peripheral and central changes) leads to

A

a reduction in sensory information necessary to control head, eyes, and body and maintain balance
- add this to a multitude of changes to other sensorystructures (vision, touch, proprioception) and loss of muscle strength = increased fall risk

43
Q

how can the brain respond during peripheral age changes vs central?

A
  • generally, have peripheral changes earlier and the brain can generally make up for it
  • initial changes might not initially manifest in terms of balance, but once we start to have central changes on top of that
    = significant drop in balance and coordination
44
Q

how do hospital admissions related to vestibular changes with age?

A
  • really start to see declines over the age of 60
  • not only have peripheral that we had before, but also central
  • impacts number of falls we have
45
Q

name 4 common vestibular pathologies

A
  • benign paroxysmal positional vertigo (BPPV)
  • vestibular neuronitis
  • labyrinthitis
  • Meniere’s disease
46
Q

describe benign paroxysmal positional vertigo

A
  • benign = harmless in the long-term
  • paraoxysal = sudden onset/recurrence of symptoms (<60 sec)
  • vetigo = sensation of spinning/dizziness (vertigo itself is a symptom, not an illness)
    *doesn’t have long term issues, just comes up
47
Q

what is BPPV caused by?

A
  • ear stones (otoconia) migrating into semi-circular canals
  • disrupting the cupula located in ampulla
    *otoconi start to move and get disripted, something happens to move them into semicircular canals
  • hitting hair cells that measure rotation
48
Q

what is the treatment of BPPV

A
  • often resolves on own, but
  • specific head manoevres can reposition debris out
    *not a ton of literature on this, can rotate head
49
Q

how rare is BBPV?

A

not super common but out of pathologies more common
- still pretty rare, less than 1% range

50
Q

what is vestibular neuronitis caused by?

A
  • inflammation of the vestibular nerve
51
Q

describe the symptoms of vestibular neuronitis

A
  • sudden vertigo that can last for several days (given its inflammation)
  • does not affect hearing (just the vestibular nerve)
52
Q

decribe the treatment of vestibular neuronitis

A
  • anti-nausea medication until inflammation reduces
  • steroids to reduce inflammation
  • physical therapy/activity can help the body compensate (PA will generally help everything because increasing the functional capacity we have)
    *trying to treat the symptom of vertigo which leads to nausea
53
Q

what is labyrinthitis caused by?

A
  • inflammation of the entire inner ear due to infection
    *translated to all of those structures, affecting both vestibular system and hearing
    *get excessive production of fluid, thows off balance
54
Q

describe the symptoms of labyrinthitis

A
  • sudden vertigo that can last for several days
  • does affect hearing
55
Q

describe the treatment of labyrinthitis

A
  • treat infection
  • anti-nausea medication until inflammation reduces
  • physical therapy/activity can help the body compensate
    *help the body have higher functional capacity so we can manage symptoms
56
Q

as compared to chickens, we can more efficiently integrate vestibular info in our _ than our _

A

vestibulo-ocular reflex, vestibulospinal tract

57
Q

which of the common vestibular athologies would be most likely to affect hearing in addition to balance?

A

labyrinthitis

58
Q

otolith organs in the vestibular system are most important for measuring acceleration and tilt, rather than head rotation. T OR F?

A

true
*angular rotation/tilt coming from semicircular canals

59
Q

what is Meniere’s disease caused by?

A
  • excessive fluid build up in inner ear (bunch of fluid throughout semicircular canals)
  • unknown why this occurs
    *one of the strangest, most severe, and most rare
60
Q

describe the symptoms of meniere’s disease

A
  • sudden episodes of: tinnitus, hearing loss, and/or vertigo
  • each episode can last minutes to hours (because fluid is increasing)
  • may occur in clusters, then subsude for years
61
Q

describe the treatment of meniere’s disease

A
  • no cure, managing symptoms
  • can lead to permanent hearing loss (if system keeps swelling*), but rare

Neural Control of Human Movement (8 decks)

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