Neuro- vestibular system Flashcards Preview

Neuroanatomy final exam > Neuro- vestibular system > Flashcards

Flashcards in Neuro- vestibular system Deck (57):
1

the vestibular labyrinth is restricted to the ________

membranous labyrinth

2

what is the vestibular labyrinth filled with?

endolymph

3

what are the 2 subdivisions of the vestibular labyrinth?

1) otolith organ
2) semicircular canals

4

what 2 structures make up the otolith organ?

a) Utriculus
b) Sacculus

5

The neuroepithelium of the otolith organ is the _____

macula

6

______ are imbedded in the macula

otoliths

7

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

otolith- static labyrinth

semicircular- dynamic labyrinth

8

the semicircular canals are continuous with the cavity of the _______

utricle

9

what part of the semicircular canal contains neuroepithelium?

the Ampulla

(the opening of the canals- holds the crista ampullaris)

10

the neuroepithelium of the semicircular canals is called the what?

crista ampullaris

11

the gelatinous ______ of the crista ampullaris floats in endolymph

cupula

12

the membranous labyrinth is suspended within the _____________

osseous labyrinth

13

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

osseous= perlymph

membranous= endolymph

14

what range of vibrations can the otolith organ sense?

0-1 Hz

15

the otolith organ is responsive to _____ acceleration

linear

like an elevator

16

the static labyrinth is activated when the head ________

tilts

17

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

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

18

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

-directionally sensitive

-measure direction and amplitude

19

the dynamic labyrinth consists of what?

3 pairs of semicircular cells

20

what is another name for the dynamic labyrinth?

semicircular canals

21

the semicircular canals sense ___________

turning movements of the head

22

the semicircular canals are sensitive to what range of vibrations?

1-10 Hz

(higher freq than otolith organ)

23

the canals of the dynamic labyrinth specifically respond to _____ acceleration

angular

24

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

provide reflex control of eye movement

25

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

False- does not move when head is at rest

26

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

cupula of the crista ampullaris deflects

endolymph remains stationary

27

when the cupula deflects, _____ fibers fire

afferent

28

the hair cells of the crista ampullaris are _____ sensitive

directionally

29

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

increase

30

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

cupula

31

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

true

32

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

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

33

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

vestibulo-ocular

34

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

the function of vestibulo-ocular reflex arc

35

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

they move in response to movement of the head

36

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

false- they move in the opposite direction

37

name the path of the ascending vestibular projections

-Medial longitudinal fasciculus = the pathway

final destination:
-Pontine tegmentum
-cerebellum

38

what are the ascending vestibular projections responsible for?

Eye movement control

(from CEREBELLUM down to the eye muscles)

39

where do the descending vestibular projections go?

spinal cord

40

what do the descending vestibular projections control?

antigravity muscles

41

the eyes can move only so far in the _____

orbit

42

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

reset their position

43

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

true

44

what is Nystagmus?

oscillating eye movements

45

the _____ system is responsible for the slow component of Nystagmus

vestibular

46

the fast components of Nystagmus cause what?

resetting of the eye

47

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

neuroepithelium of the ampule
-horizontal semicircular canal

48

what happens to the eyes during the caloric test?

moving horizontally (slow phase)

snapping back quickly (fast phase)

49

what does the acronym COWS stand for?

Cold opposite, warm same

50

what will happen to the subject during the caloric test?

they experience the illusion that the room is rotating around them

51

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

true

52

where is the vestibular cortex found?

posterior insular cortex

53

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

Terminates in the pontine tegmentum & cerebellum

54

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

vestibular nuclei

55

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

Medial longitudinal fasciculus

(connects vestibular nuclei with abducens nuclei)

56

What is the location of the primary vestibular cortex?

Posterior insular cortex

-part of the parietal lobe

57

The vestibulo-ocular reflex is normally inhibited by the _________

cortex