Vestibular System

Question 1

the vestibular system can be considered our sense of _________

Answer 1

equilibrium; keeping yourself stable despite world around you

Question 2

4 things involved in the vestibular system

Answer 2

spatial orientation

vestibulo-ocular reflex

balance

vestibulo-autonomic reflexes

Question 3

in the vestibular system, you are constantly …

Answer 3

adjusting your position yet you always feel stable

Question 4

issues tied to vestibular system

Answer 4

spatial disorientation
- any impairment of spatial orientation

dizziness
- nonspecific spatial disorientation

vertigo
- a sensation of rotation or spinning

imbalance

blurred vision

illusory self-motion

Question 5

spatial orientation

Answer 5

perception of angular motion, linear motion, and overall tilt

examples:
- angular: rotation of head from side to side
- linear: your bus slams on the breaks
- tilt: your orientation with respect to gravity

Question 6

balance

Answer 6

processes of postural control by weight distribution, allowing us to stay upright and stable

Question 7

vestibulo-ocular reflex

Answer 7

the countermovement of your eyes in response to a head movement in order to maintain stable fixation
- shaking finger = blur, shaking head = still finger

Question 8

vestibulo-autonomic responses

Answer 8

vestibular system communicates with autonomic system like blood pressure, gastrointestinal, etc. about equilibrium
- things like motion sickness tied to this, and control of blood flow when standing vs. laying

Question 9

sense of equilibrium is ______

Answer 9

active

Question 10

afferent and example

Answer 10

external inputs about the world

world info going to brain

ex. graviception, vestibular system is how your body seemingly automatically understands gravity

Question 11

efferent

Answer 11

inputs about muscle movements

info exiting brain going to muscles, guiding movement

Question 12

semicircular canals

Answer 12

3 of them!

toroidal (donut like) tubes that sense changes in angular velocity/acceleration

Question 13

otolith organs

Answer 13

2 of them!

mechanical structures that sense linear acceleration and gravity

Question 14

when talking about vestibular sensing we’ll talk about 3 directional planes:

Answer 14

x (forward and back)
y (left/right)
z (up/down)

Question 15

orientation is relative to your ____

Answer 15

head

Question 16

linear motion can be represented in terms of … while angular motion can be represented as …

Answer 16

change along x, y, z; rotation along x, y, z

Question 17

roll vs. pitch vs. yaw

Answer 17

roll: rotation on x-axis

pitch: rotation on y-axis

yaw: rotation on z-axis

Question 18

moving at a constant velocity does not produce response in the ______ ________

Answer 18

vestibular organs

part of why you don’t feel like you’re moving in your car or the earth spinning

Question 19

how do we transduce “equilibrium”?

Answer 19

hair cells and mechanoreception

Question 20

2 difference between vestibular hair cells and auditory hair cells?

Answer 20

vestibular is based on head movement instead of sound vibration

vestibular hair cells release a baseline constant amount of neurotransmitter at “rest”

Question 21

bending the stereocilia in vestibular hair cells can result in … based on the direction (what direction?)

Answer 21

depolarization (left/towards kinocilium) or hyperpolarization (right/towards shortest stereocilia)

Question 22

any hair cell can code a particular set of ______/_______

Answer 22

directions/rotations

Question 23

kinocilium

Answer 23

largest stereocilia

Question 24

bony labyrinth

Answer 24

each is ~3/4 of a toroid shape (donut) filled perilymph fluid

bony exterior to keep in place

Question 25

membranous labyrinth

Answer 25

inside bony labyrinth, separated by the perilymph is a smaller, membrane toroid filled with *endolymph fluid* jelly/membrane interior, change info for how fluid presses against hair cells

Question 26

the bony and membranous canals/labyrinths meet at a chamber called the

Answer 26

vestibule

Question 27

semicircular canals run ______ to each other

Answer 27

perpendicular

Question 28

horizontal semicircular canal rotates on __-axis (and term)

Answer 28

z; yaw

Question 30

anterior and posterior semicircular canal rotates on both __-axis' (and term)

Answer 30

x+y; roll+pitch

Question 31

ampulla

Answer 31

contain the structures that allow for transduction where semicircular canals swell into

Question 32

features inside the ampulla

Answer 32

crista - ~7000 hair cells are anchored and connected to nerve fibers cupula - a jelly-like, elastic dam into which stereocilia project

Question 33

hair cells in each ampulla are arranged in the same direction with respect to their

Answer 33

kinocilium

Question 34

as you rotate tour head, endolymph movement lags due to _____

Answer 34

inertia

Question 35

the endolymph presses in the _____ direction on the cupula, deflecting the ________ of the hair cells

Answer 35

opposite; stereocilia

Question 36

your two ears respond in _________ fashions in relation to the endolymph movement; meaning when one side is depolarized, the other is _________

Answer 36

complementary; hyperpolarized

Question 37

opposing posterior/anterior canals have _____ planes, so the push/pull complementary nature is between posterior/anterior from opposite ears (what does this mean)

Answer 37

parallel; one sides anterior is opposite of the other sides posterior canal

Question 38

since afferent are firing steadily, the can code ...

Answer 38

both decreases and increases in angular acceleration and amount is based on how deflected the hair cells become

Question 39

why do we use sine waves to measure back and forth movements of the head?

Answer 39

many movements return to baseline and you can also deconstruct complex movements into simple sine waves

Question 40

2 organs that sense acceleration and tilt (overall term for them both then individual names and differences)

Answer 40

otolith organs - utricle: 30,000 hair cells - saccule: 16,000 hair cells

Question 41

macula

Answer 41

"spot" present on both otolith organs, specialized to detect linear acceleration and gravity/detect shear forces

Question 42

the macula are planar, so the utricle macula is ______ while the saccular macula is ______

Answer 42

horizontal; vertical

Question 43

striola

Answer 43

hair cells aligned relative to a midline structure in the macula

Question 44

otoconia

Answer 44

ear stones present on top of stereocilia in macula exacerbate the inertia of the gel membrane and also weigh it down relative to gravity

Question 45

______ accelerations move otoconia more; meaning that change in receptor's potential is _______ to the magnitude of that movement

Answer 45

large; proportional

Question 46

3 ways to test vestibular perception

Answer 46

threshold estimation - what is the minimum motion needed to correctly perceive motion direction magnitude estimation - participants report how much they think they tilted, rotated, or translated matching - participants are tilted and then orient a line with the direction of gravity. done in a dark room with only the line visible to avoid any visual cues

Question 47

velocity storage

Answer 47

perception of "stop" lags behind the time course of the neurons' habituation

Question 48

when reproducing translations, the vestibular system is not only good at producing ______, but also _____

Answer 48

direction; velocity

Question 49

vestibular system detects velocity by doing ________ ________

Answer 49

mathematical integration

Question 50

which part of the vestibular system physically causes hair cells to bend in response to fluid inertia from angular motion? a. cupula b. saccule c. utricle d. ampulla

Answer 50

cupula

Question 51

do you know what angular rotation and tilt looks like on graphs?

Answer 51

yes, on slide 6 for touch presentation

Question 52

is there a vestibular cortex?

Answer 52

nope

Question 53

vestibulo-spinal responses

Answer 53

a set of reflexes that help you almost automatically adjust your body as you transfer weight

Question 54

vestibular organs project to the _______ _____ in the brain stem

Answer 54

vestibular nuclei

Question 55

the vestibular nuclei project to _______ where it is integrated with muscle/skin input and from there, goes to multiple cortical regions, many of which also receive visual input --> _______ ______

Answer 55

thalamus; multisensory integration

Question 56

multisensory integration

Answer 56

vestibular inputs combined at multiple points with other senses

Question 57

vection

Answer 57

anything that gives you a sense of motion/physical movement/rotation despite not moving at all ex. being on a boat all day and then stepping off but still feeling as though you are on a boat