Vestibular System Flashcards

1
Q

hair cell

A

transducer-do not fire APssynapse with primary afferents

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2
Q

primary afferents

A

-axons in vestibulocochlear nerve-cell bodies in vestibular ganglion (petrous portion of temporal bone)don’t decussate

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3
Q

vestibular system

A

signals posntion and movement-detects acceleration and gravityseries of membranous tubes-in temporal bone

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4
Q

targets of vestibular info

A

cortexcerebellumspinal cord-vestibulospinal tractcranial nerve III, IV, VIreticular formation

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5
Q

hair cell anatomy

A

tallest sterocilia - kinociliumstereocilia on apical surface

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6
Q

apical vs. basilar hair cell

A

endolymph - apical-high Kperilymph - basilar-low K

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7
Q

baseline activity of hair cell

A

results in baseline activity of afferent nerveincrease or decrease firing

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8
Q

kinocilium

A

reference

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9
Q

movement of stereocilia

A

towards kinocilium - depolarizationaway from kinocilium - hyperpolarization

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10
Q

tip links

A

connect stereocilia

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11
Q

peripheral apparatus

A

tubes in temporal bone-nerves through internal acoustic meatussetup orients and applies mechanical force to hair cell stereocilia

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12
Q

ampulla

A

ends of semicircular ductswhere hair cells are

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13
Q

otolith organs

A

where semicircular ducts attachutricle - semicirc duct attachmentsaccule

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14
Q

angular acceleration

A

semicircular ducts

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15
Q

linear acceleration

A

otolth organs

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16
Q

utricle

A

horizontal acceleration

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17
Q

saccule

A

vertical acceleration

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18
Q

fluid lags

A

when head rotation occurs

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19
Q

head rotation

A

tubes rotate-endolymph lags behind-this is detected by hair cells in ampulla

20
Q

functional pairs

A

semicircular ducts function in right/left pairsrespond oppositely in response to head turn-gives differential signal

21
Q

differential signal

A

important because it increases sensitivity of the system-detect minute accelerations

22
Q

otolith organs

A

sense linear acceleration/gravity

23
Q

utricle

A

horizontal

24
Q

saccule

A

vertical

25
Q

maculae

A

in utricle and saccule-has hair cellscovered by otolith membranes-membrane has greater mass due to ear stones

26
Q

striola

A

division of maculae-hair cells oppositely polarized in each halforiented in curve

27
Q

each maculae

A

gives differential signal

28
Q

maculae orientation

A

every plane in x and y axis

29
Q

peripheral apparatus

A

include semicircular ducts and otolith organs-detect acceleration and gravity

30
Q

primary efferents

A

cell bodies in vestibular ganglion

31
Q

axons of primary efferents

A

vestibulocochlear nervemost synapse in vestibular nuclei-some to cerebellum (ipsilateral)

32
Q

vestibular nuclei

A

four each side-ventral and lateral to 4th ventricle-distribute info and regulate reflexes

33
Q

vestibular nuclei activity

A

have baseline

34
Q

targets of vestibular information

A

cerebellumreticular formationcerebral cortexspinal cortex (LVST/MVST)cranial nerve III, VI, VI-eye movement opposite to keep image on retina

35
Q

vestibuloocular reflex

A

moving head allows you to focus on moving words-maintain gaze during head movements

36
Q

path of vestibuloocular reflex

A

axons in MLF - ascend to motor nuclei of III, IV, VI

37
Q

abducent nuclei

A

cell bodies that are LMNs-ipsilateral lateral rectus m.

38
Q

trochlear nuclei

A

superior oblique m.

39
Q

oculomotor nuclei

A

medial rectus, and others

40
Q

nystagmus

A

series of back and forth eye movements-slow one way, fast other way-can be pathologic of normalslow - VORfast - visual motor systemnamed for direction of fast phase

41
Q

slow nystagmus movement

A

slow - VOR

42
Q

vestibulocollic reflex

A

postural muscles of neck-extension ipsilateral to depolarized hair cellsbilateral projectionmedial vestibulospinal tract-descending MLF/MVST

43
Q

vestibulospinal reflex

A

through lateral vestibulospinal tractipsilateral projectionto LMNs in axial and antigravity muscles of limb

44
Q

vestibular reflexes

A

based on comparison of differential signalsasymmetry of signals that drives reflexes

45
Q

lesions

A

irritativedestructive - more common

46
Q

hair cells

A

can be killed with antibiotices

47
Q

fast phase nystagmus

A

away from lesionhead/body tilt, leaning and falling toward lesion