06a: Peripheral Vestibular System Flashcards Preview

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Flashcards in 06a: Peripheral Vestibular System Deck (44)
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1
Q

The vestibular receptors are actually (X).

A

X = hair cells

2
Q

Where are the vestibular receptors located?

A
  1. Semicircular canals

2. Utricle and saccule (maculae)

3
Q

Vestibular nuclei send axons to:

A
  1. Cerebellum
  2. Extra-ocular muscle nuclei
  3. Reticular formation
  4. SC
4
Q

Vestibular receptors are divided into which groups?

A
  1. Static receptors

2. Kinetic receptors

5
Q

List the (X) vestibular receptors, which respond to linear accelerations.

A

X = static

Maculae of the utricle and saccule

6
Q

List the (X) vestibular receptors, which respond to angular accelerations.

A

X = kinetic

Cristae of semicircular canals

7
Q

Which vestibular receptors play prominent role in signaling static position of head?

A

Static receptors

8
Q

Which vestibular receptors play prominent role in signaling angular velocity of (rotating) head?

A

Kinetic receptors

9
Q

List the three major functions of the vestibular system.

A
  1. Subjective sensation of motion/spatial orientation
  2. Postural control
  3. Stabilizing eyes during head movement
10
Q

T/F: Most of vestibular system’s actions are reflexive (occur at unconscious level).

A

True

11
Q

T/F: Our perception of spatial orientation is essentially completely dependent on vestibular input.

A

False

12
Q

T/F: At rest, vestibular primary afferents discharge action potentials.

A

True

13
Q

Bending of (X) toward kinocilium causes (Y). And away causes (Z).

A
X = sterocilia;
Y = depolarization of HCs
Z = hyper-polarization of HCs
14
Q

Bending of (X) toward kinocilium is associated with (increase/decrease) in firing frequency of (Y).

A

X = sterocilia;
Increase;
Y = primary afferent fibers

15
Q

The amplitude of depolarization/hyperpolarization of hair cells depends on:

A

Direction of bending of cilia, relative to kinocilium

16
Q

Bending of cilia perpendicular to kinocilium will (depolarize/hyperpolarize) HC.

A

Neither - no change in HC voltage if perpendicular

17
Q

In the (X), the macula is approximately horizontal when body is upright. And in the (Y), it’s vertical.

A
X = utricle;
Y = saccule
18
Q

In the otolith organs, the cilia are embedded in (X) containing (Y) called “otoconia”.

A
X = gelatinous material (otolithic membrane)
Y = CaCO3 crystals
19
Q

Otoconia function in bending motion.

A

Make otoliths denser than endolymph, causing Otolithic membrane (and cilia of HCs) to sag

20
Q

Otoconia function in linear acceleration.

A

Heavier otoliths lag behind (due to inertia), bending cilia of HCs

21
Q

Degree of tilt/head movement is indicated by (X).

A

X = frequency of firing of primary afferents

22
Q

The direction of movement is indicated by (X).

A

X = which primary afferents (or HCs) are active

23
Q

The magnitude of head movement is indicated by:

A

Change in rate of firing of primary afferent fibers

24
Q

In semicircular canals, the HCs are embedded in (X), which extends into the (Y) fluid that fills the canals.

A
X = cupula (gelatinous material)
Y = endolymph
25
Q

Why (does/doesn’t) the cupola move with respect to the (X) during linear acceleration?

A

Doesn’t;
X = semicircular canal;

Same specific gravity as endolymph that fills canal

26
Q

Movement of endolymph in (X) causes (Y) to swing like a door.

A
X = semicircular canal;
Y = cupula
27
Q

On each side of the head, there are (X) number of semicircular canals, all (parallel/perpendicular) to each other. List them.

A

X = 3; perpendicular;

Horizontal, anterior, posterior

28
Q

List the complimentary pairs of the semicircular canals.

A
  1. L and R horizontal
  2. L posterior with R anterior
  3. R posterior with L anterior
29
Q

Horizontal semicircular canals are perfectly horizontal if head is in which position?

A

Tilted forward 30 degrees

30
Q

Depolarization of hair cells is due to (X) ion moving down (chemical/electrical) gradient from (Y) space to (Z) space.

A

X = K+
Electrical;
Y = endolymph
Z = HC

31
Q

Endolymph has high concentration of (X) ions and low concentration of (Y) ions. What’s the typical potential (in mV) of this space?

A
X = K+
Y = Na and Ca

+80 mV

32
Q

The (X) membrane separates the endolymph from the (Y).

A
X = reticular
Y = perilymph
33
Q

Perilymph has high concentration of (X) ions and low concentration of (Y) ions. What’s the typical potential (in mV) of this space?

A
X = Na
Y = K

0 mV

34
Q

The hair cells have high concentration of (X) ions and low concentration of (Y) ions. What’s the typical potential (in mV) of this space?

A
X = K
Y = Na

-40 mV

35
Q

In any one semicircular canal, how do the HCs differ in orientation?

A

They don’t! Identical orientation

36
Q

Saccule respons best to movements in which plane?

A

Saggital (front/back movement)

37
Q

Utricle respons best to movements in which plane?

A

Frontal (L/R movement)

38
Q

The striola is present in (otolith organs/semicircular canals) and functions to:

A

Otolith organs;

Divides hair cells into two populations with opposite polarities

39
Q

The macula of the otolith organs is analogous to (X) of semicircular canal. Define these.

A

X = Crista;

Sensory epithelium that contains the hair cells

40
Q

Semicircular canals respond only to which type of movement?

A

Changes in velocity (angular acceleration)

41
Q

You turn your head to the right, primarily activating (X) vestibular structures. Describe direction of fluid flow.

A

X = horizontal semicircular canals;

R: toward ampulla
L: away from ampulla

42
Q

You turn your head to the right. Where does the de/hyper-polarization happen?

A

Depolarization in R horizontal semicircular canal. Hyperpolarization in L canal.

43
Q

T/F: Difference in response of semicircular canal pairs is due to opposite orientation of hair cells and kinocilium between the pairs.

A

False - due to opposite movement of fluid within canal pairs

44
Q

Pressure exerted by fluid on cupula is in the (same/opposite) direction as the head rotation.

A

Opposite