Vestibular System Flashcards

1
Q

Inner ear is called the ____

A

labyrinth

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2
Q

Osseus Labyrinth components (3)

A

Cochlea
Vestibule
Semicircular Canals

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3
Q

Membranous Labyrinth Components (4)

A

Cochlear duct
Utricle
Saccule
Three semicircular ducts

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4
Q

Endolymph is high in

A

Potassium

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5
Q

Perilymph is high in

A

Sodium

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6
Q

Vestibule

A

Large chamber adjacent to the middle ear

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7
Q

Semicircular canals

A

Three semicircular channels in bone, each is orthogonal to the other two

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8
Q

Cochlea

A

spiral chamber that is related to hearing

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9
Q

Membranous Labyrinth contains:

A

endolymph

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10
Q

Cochlear duct

A

Related to hearing

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11
Q

Utricle

A

Larger of 2 sacs within the vestibule

Contains Otolith membrane and macula

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12
Q

Saccule

A

Smaller of 2 sacs within the vestibule

Contains otolith membrane and macula

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13
Q

3 semicircular ducts

A

Each have an ampulla which contains a crista ampullaris and a cupulla

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14
Q

Crista Ampullaris

A

crest bearing sensory receptor cells

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15
Q

Cupulla

A

Gelatinous membrane

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16
Q

The Vestibular Apparatus Consists of (3)

A

Macula of the utricle
Macula of the saccule
Crista ampullaris

17
Q

Macula of the utricle

A

Horizontally oriented and detects LINEAR ACCELERATION in the horizontal plane (side to side)

18
Q

Macula of the saccule

A

Detects LINEAR ACCELERATION in the vertical plane (up and down)

19
Q

Crista ampullaris

A

1 in each semicircular duct ampulla

Detects ANGULAR ACCELERATION directed along the plan in which the duct is positioned

20
Q

Movement of the overlying otolith membrane results in deflection of ______

A

Sterocilia

21
Q

Deflection TOWARD the kinocilium mechanically opens ion channels. This allows ______ to flow from endolymph into the hair cell, thus _______ the receptor cell membrane

A

Potassium

Depolarizing

22
Q

Depolarization of the receptor cell enables _____ influx and release of ______ from synaptic vesicles which are located along the basolateral region of the receptor cell. The ______ neurotransmitter triggers action potentials in afferent axons on the vestibular nerve.

A

Calcium

Glutamate

23
Q

Deflection away from the Kinocilium _____ ion channels and ultimately _____ glutamate release

A

Closes

Reduces

24
Q

In the crista ampullaris, sterocilia are embedded in a geltanious membraned called a ______

A

Cupula

25
Q

In the macula, stereocilia are embedded in a gelatinous _______

A

Otolith Membrane

26
Q

Otolith membrane contains

A

Calcium concretions (ear stones)

27
Q

Receptor cells are ______ active and vestibular nerve axons _____ conduct action potentials to the brainstem. Thus the movement of sterocilia results in an ______ or a _____ in the rate of spontaneous activity.

A

Spontaneously
Continually
Increase
Decrease

28
Q

Vestibular nerve fibers (axons from the neuronal cell bodies of the vestibular ganglion) travel from the ___ ___ to the ____

A

Inner Ear

Brain

29
Q

Vestibular nerve fibers synapse in _____ _____ of the brainstem and in the ___ or ____ of the cerebellum.

A

Vestibular Nuclei

Nodulus or flocculus

30
Q

Four vestibular nuclei are located bilaterally in the medulla and the pons. The nuclei receive input from the _______ and project to: (4)

A

Vestibular Nerve

  1. Cerebellum (flocculu-nodular lobe)
  2. Reticular formation
  3. Spinal cord via the lateral vestibulospinal tract activates limb extensor mm via alpa and gamma neurons
  4. Neurons controlling eye and neck mm via the MEDIAL LONGITUNDINAL FASCICULUS
31
Q

Eyes are shifted in a direction ____ to the direction that the head is accelerated

A

Opposite

32
Q

Vestibular nuclei on the right side dominate activity in the ______ Abducens nucleus and _____ Oculomotor nucleus, causing both eyes to move _____

A

Left
RIght
Left

33
Q

In general, vestibular nuclei push the eyes _______

A

contralaterally

34
Q

Extensor muscles are contracted ________ which the head is accelerating

A

on the side toward

35
Q

Vestibular Syndrom symptoms (3)

A

Head Tilt
Stumbling
Nystagmus

36
Q

Slow phase of nystagmus is directed ____

A

toward the side of the lesion

37
Q

Vestibular nystagmus is generated reflexly by ___ ___ in response to angular accelreration

A

Vestibular

38
Q

Opticokinetic nystagmus is generated by ____ when focusing on moving objects (e.g. a train passenger focusing on telephone polls)

A

Cerebral cortex