Neuro- vestibular system

Question 1

the vestibular labyrinth is restricted to the ________

Answer 1

membranous labyrinth

Question 2

what is the vestibular labyrinth filled with?

Answer 2

endolymph

Question 3

what are the 2 subdivisions of the vestibular labyrinth?

Answer 3

1) otolith organ

2) semicircular canals

Question 4

what 2 structures make up the otolith organ?

Answer 4

a) Utriculus

b) Sacculus

Question 5

The neuroepithelium of the otolith organ is the _____

Answer 5

macula

Question 6

______ are imbedded in the macula

Answer 6

otoliths

Question 7

the otolith organ is known as the “_______ labyrinth”, while the semicircular canal is known as the “______ labyrinth”

Answer 7

otolith- static labyrinth

semicircular- dynamic labyrinth

Question 8

the semicircular canals are continuous with the cavity of the _______

Answer 8

utricle

Question 9

what part of the semicircular canal contains neuroepithelium?

Answer 9

the Ampulla

the opening of the canals- holds the crista ampullaris

Question 10

the neuroepithelium of the semicircular canals is called the what?

Answer 10

crista ampullaris

Question 11

the gelatinous ______ of the crista ampullaris floats in endolymph

Answer 11

cupula

Question 12

the membranous labyrinth is suspended within the _____________

Answer 12

osseous labyrinth

Question 13

the osseous labyrinth is filled with _______, while the membranous is filled with ______

Answer 13

osseous= perlymph

membranous= endolymph

Question 14

what range of vibrations can the otolith organ sense?

Answer 14

0-1 Hz

Question 15

the otolith organ is responsive to _____ acceleration

Answer 15

linear

like an elevator

Question 16

the static labyrinth is activated when the head ________

Answer 16

tilts

Question 17

what happens in the static labyrinth when the head is tilted?

Answer 17

the otoliths embedded in the macula will deflect the hairs (stereocilia) of the hair cells

Question 18

the hair cells of the static labyrinth are _______ sensitive. what can they measure?

Answer 18

• directionally sensitive

- measure direction and amplitude

Question 19

the dynamic labyrinth consists of what?

Answer 19

3 pairs of semicircular cells

Question 20

what is another name for the dynamic labyrinth?

Answer 20

semicircular canals

Question 21

the semicircular canals sense ___________

Answer 21

turning movements of the head

Question 22

the semicircular canals are sensitive to what range of vibrations?

Answer 22

1-10 Hz

higher freq than otolith organ

Question 23

the canals of the dynamic labyrinth specifically respond to _____ acceleration

Answer 23

angular

Question 24

what is the primary function of the dynamic labyrinth (semicircular canals)?

Answer 24

provide reflex control of eye movement

Question 25

T/F: the endolymph of the semicircular canals is constantly moving

Answer 25

False- does not move when head is at rest

Question 26

``` function of the semicircular canals: when the head turns, the _____ will deflect while the _____ remains stationary ```

Answer 26

cupula of the crista ampullaris deflects endolymph remains stationary

Question 27

when the cupula deflects, _____ fibers fire

Answer 27

afferent

Question 28

the hair cells of the crista ampullaris are _____ sensitive

Answer 28

directionally

Question 29

when the head moves toward midline, the hair cells of horizontal semicircular canals will ______ their firing rate

Answer 29

increase

Question 30

when the head turns, the ______ on one side deflect toward midline, while the ______ on the opposite side deflects away

Answer 30

cupula

Question 31

T/F: deflecting the cupula away from the midline will decrease the firing rate of hair cells

Answer 31

true

Question 32

turn your head to the right. what happens to the cupula on the right side of the head? what does this cause?

Answer 32

cupula on right will deflect medially | - this increases the firing rate of the crista ampullaris

Question 33

the eye responds via the ____-_____ to deflect the eye based on info from semicircular canals

Answer 33

vestibulo-ocular

Question 34

the Doll's Eye Phenomenon is a measure of what?

Answer 34

the function of vestibulo-ocular reflex arc

Question 35

during the doll's eye phenomenon, what happens to the eyes?

Answer 35

they move in response to movement of the head

Question 36

T/F: the eyes move in the same direction as the head during the doll's eye phenomenon

Answer 36

false- they move in the opposite direction

Question 37

name the path of the ascending vestibular projections

Answer 37

-Medial longitudinal fasciculus = the pathway final destination: - Pontine tegmentum - cerebellum

Question 38

what are the ascending vestibular projections responsible for?

Answer 38

Eye movement control | from CEREBELLUM down to the eye muscles

Question 39

where do the descending vestibular projections go?

Answer 39

spinal cord

Question 40

what do the descending vestibular projections control?

Answer 40

antigravity muscles

Question 41

the eyes can move only so far in the _____

Answer 41

orbit

Question 42

when the eyes reach a certain point, they do what?

Answer 42

reset their position

Question 43

T/F: the velocity of the eyes resetting is very fast

Answer 43

true

Question 44

what is Nystagmus?

Answer 44

oscillating eye movements

Question 45

the _____ system is responsible for the slow component of Nystagmus

Answer 45

vestibular

Question 46

the fast components of Nystagmus cause what?

Answer 46

resetting of the eye

Question 47

water or air introduced into the external auditory canal will stimulate what?

Answer 47

neuroepithelium of the ampule | -horizontal semicircular canal

Question 48

what happens to the eyes during the caloric test?

Answer 48

moving horizontally (slow phase) snapping back quickly (fast phase)

Question 49

what does the acronym COWS stand for?

Answer 49

Cold opposite, warm same

Question 50

what will happen to the subject during the caloric test?

Answer 50

they experience the illusion that the room is rotating around them

Question 51

T/F: if cold water is used for the caloric test, the fast phase will be in the opposite direction

Answer 51

true

Question 52

where is the vestibular cortex found?

Answer 52

posterior insular cortex

Question 53

Name the brain structure in which primary afferents of the semicircular canals and otolith organ terminate.

Answer 53

Terminates in the pontine tegmentum & cerebellum

Question 54

Within which region of the pontine tegmentum/cerebellum do the eye-movement controlling fibers terminate?

Answer 54

vestibular nuclei

Question 55

Name the myelinated pathway that links the vestibular nuclei with the eye movement-control nuclei

Answer 55

Medial longitudinal fasciculus | connects vestibular nuclei with abducens nuclei

Question 56

What is the location of the primary vestibular cortex?

Answer 56

Posterior insular cortex -part of the parietal lobe

Question 57

The vestibulo-ocular reflex is normally inhibited by the _________

Answer 57

cortex