Vestibular System

Question 1

what area of the vestibular system measures angular motion?

Answer 1

semicircular canals

Question 2

what area of the vestibular system measures linear motion?

Answer 2

vestibule

Question 3

multimodal convergence?

Answer 3

all of the systems help to keep you coordinated. Ex. stand on one leg with eyes close and use 1 finger on table to balance

Question 4

1st writing response?

Answer 4

lift head

Question 5

where is endolymph located?

Answer 5

inside membranous labyrinth of cochlea

Question 6

what is endolymph?

Answer 6

identical to CSF except with high potassium

Question 7

where is perilymph located?

Answer 7

inside membranous labyrinth of the semicircular canals

Question 8

what is perilymph?

Answer 8

identical to CSF except high sodium

Question 9

orientation of the horizontal canal?

Answer 9

parallel to gravity (30 degrees up)- this is why you lean your head forward to optimize the vestibular and visual field when running.

Question 10

what type of cells are the hair cell in the inner ear?

Answer 10

modified epithelial cells

Question 11

what are the 6 steps for how a hair cell transmits a signal?

Answer 11

1. movement of head
2. filament btwn cillia is pulled
3. potassium stretch channels open
4. potassium removed
5. high potassium depolarizes, calcium channels open and neurotransmitter released
6. neuronal (ganglion) projection - receives neural transmission from epithelial cells

Question 12

what regulates the discharge rate of the hair cells?

Answer 12

potassium concentration

- hair cells have a high tonic firing rate

Question 13

what are two structures that help to overcome inertia?

Answer 13

copula and otolith membrane

Question 14

what is the copula?

when is it used?

Answer 14

• filled with high viscosity fluid that helps to transmit a signal from one side to the other and to overcome inertia
• angular (rotational) movement

Question 15

function of the utricle

Answer 15

integrate angular & linear movement

Question 16

function of the saccule

Answer 16

measure linear movement (gravity)

Question 17

what happens if you break the otolith membrane?

Answer 17

vertigo

Question 18

interactions of the otoconia and otolith membrane?

Answer 18

calcium carbonate crystals of the otoconia go up and then come back down on the otolith membrane.
-linear acceleration

Question 19

linear acceleration

Answer 19

gravitational

Question 20

angular accelecation

Answer 20

rotational movement

Question 21

function of the vestibulocerebellar tract?

Answer 21

coordinate angular motion to the cerebellum (by passes the cranial nerves)

Question 22

angular epithelial cells in relation to the central vestibular nucleus go to what 4 locations?

Answer 22

angular- roational goes up!!

1. Medial vestibular nucleus
2. Lateral vestibular nucleus
3. Superior vestibular nucleus
4. Juxtarestiform body (cerebellum)

Question 23

linear epithelial cells in relation to the central vestibular nucleus go to what 4 locations?

Answer 23

linear - gravity goes down!!!

1. Medial vestibular nucleus
2. Lateral vestibular nucleus
3. Inferior vestibular nucleus
4. Cell group Y

Question 24

what is the slow phase of the vestibuloocular pathway?

Answer 24

turn head, eyes move opposite direction

- eyes move off the point of attention

Question 25

what is the fast phase of the vestibuloocular pathway?

Answer 25

turn head, eyes move back to the target very fast

Question 26

what happens in caloric nystagmus when warm water is added to the right ear?

Answer 26

eyes go slowly to the ground first and then rapidly to the ears

Question 27

what happens in caloric nystagmus when cold water is added to the right ear?

Answer 27

eyes go slowly to the sky and then fast to the ground

Question 28

what happen to the endolymph when warm water is added to the ear?

Answer 28

it rises

Question 29

the vestibulo-thalamic cortical networks does what?

Answer 29

conscious perception of motion = spatial orientation

Question 30

destination of the vestibulo-thalamic cortical networks?

Answer 30

VPL, VPM, Vi of Thalamus to cortex

Question 31

function of the vestibulospinal pathway?

Answer 31

coordinate head movements, posture axial muscular coordination

Question 32

a person with a left nystagmus in the vestibulospinal pathway - what happens?

Answer 32

they will fall / stumble to the right