Auditory and vestibular system Flashcards Preview

Anatomy Final > Auditory and vestibular system > Flashcards

Flashcards in Auditory and vestibular system Deck (65):
1

What are the two divisions of CN VIII?

Cochlear = sound
Vestibular = head positions and movement.

2

Auditory & vestibular receptors are both innervated by _____.

CN VIII

3

The _______ is the outer most layer of the cochlea, vestibule and Semicircular canals.

Bony labyrinth

4

What lines the inside of the bony Labyrinth?

The membranous labyrinth = tube suspended in bony labyrinth.
- creates duct in each semicircular canal
- creates cochlear duct in cochlea
- 2 enlargements in the vestibule (Utricle & Saccule)

5

The _____ is the enlargement of the vestibule that is attached to the semicircular ducts.

Utricle

6

The _______ is the enlargement of the vestibule that is connected to the cochlear duct and utricle.

Saccule

7

Perilymph is found in the ______ and is similar to ______ in composition.

Bony labyrinth
CSF

8

Endolymph is found in the________ and is similar to ______ in composition.

Fills membranous Labyrinth
Similar to intracellular fluid

9

What produces endolymph?

Specialized cells of the Cochlea
*Resorbed in Endolymphatic sac

10

Meneires disease cause and symptoms?

- Obstruction of flow of endolymph in membranous labyrinth.
- transient attacks of vertigo, nausea, hearing loss and tinnitus.

11

______ are Auditory and vestibular receptor cells.

hair cells

12

_________ hair cells lack Kinocilium.

Cochlear

13

Hair cells have microvilli known as ________ arranged in graduated rows with ______ towards one side.

- Stereo cilia
- Tallest

14

Where does the Kinoculium reside?

near the tallest stereo cilia
- in the semicircular ducts, utricle & saccule *Not cochlear

15

How is receptor potential transduced?

gelatinous material at tips of kinocilium and stereo cilia. movement of G material causes deflection of stereo cilia.

16

Deflection toward the tallest stereo cilia causes what?

Depolarization of hair cell

17

Deflection away from tallest stereo cilia causes what?

Hyper polarization of hair cell

18

Deflection in perpendicular plane causes what?

Nothing!

19

________ moves perilymph.

Stapes

20

_______ & ______ convey airborne sound to fluid-filled inner ear.

Outer & middle ear

21

Tympanic membrane is _____ the size of the stapes footplate. What does this mean?

15x
= stapes vibrations have more force/unit area.

22

_______ pulls stapes away from oval window of the Cochlea, stiffening the Ossicular chain. What does this do?

Stapedius muscle (Innervated by VII)
= Blocks sounds of own voice (Spasm can cause clicking sound in ear when speaking.)

23

_______ pulls the malleus in toward the middle ear, stiffening the ossicular chain. What does this do?

Tensor Tympani muscle (innervated by V)
= Blocks chewing sound; can anticipate loud sounds and cans spasm, causing tinnitus at low frequency.

24

What are the 3 structures of the Cochlea?

Scala Vestibuli (Sup.)
Scala media (Med)
Scala tympani (Inf)

25

________ is a perilymphatic space, continuous with vestibule.

Scala Vestibuli

26

(structure of cochlea)______ contains endolymph.

Scala media

27

_____ is a perilymphatic space, ends blindly at round window.

Scala tympani

28

What is the Organ of Corti?

A strip of cells (Made of two groups) that rests on basilar membrane.

29

Describe the 2 groups of cells that make up the Organ of corti.

1. Inner hair cells = not attached to gelatinous tectorial membrane,instead its stimulated by endolymph movement across stereo cilia.
2. Outer hair cells = Stereo cilia insert into tectorial membrane. (Vibrations in basilar membrane causes oscillations in membrane potential of hair cells.

30

Starting at stapes, describe transduction of sound/wave....

1. stapes movement causes pulse in scala vestibuli that leads to a traveling wave of deformation in basilar membrane.
2. Mechanical properties differ along the length of basilar membrane so location of peak amplitude deteremines of frequency of it.
3. "Mechanical tuning" of basilar membrane is the beginning of tonotopic organization of auditory system.
4. Particular frequencies are mapped to specific regions of relay nuclei and cortex.

31

How does a cochlear implant work?

takes advantage of the tonotopic organization cochlea.

32

_________ is the primary ascending auditory pathway. Where are the fibers from?

lateral lemnisucs pathway *Constists mostly of fibers from dorsal cochlea nucleus)

33

Where the Primary auditory cortex located?

In the transverse temporal gyro of Heschl (Superior surface of temporal lobe)

34

_____ is important in sound localization.

Superior olivary nucleus

35

How and where does the Superior olivary nucleus receive fibers?

Receives fibers from bilateral cochlear nuclei, fiber cross midline they trapezoid body.
- two sub nuclei = medial (arrival time comparison) & lateral.

36

___________ detects linear and angular acceleration.

Vestibular divison of VIII
- Regulates posture, coordinates eye & head movements.
- Maintains orientation in response to movements.

37

Whats the main difference between the semicircular duct, utricle, saccule and the cochlea duct?

Semicircular ducts, saccule & utricle are suspended in bony labyrinth where as the cochlea duct is stretched.

38

Each ampulla of the semicircular ducts contain _______.

Crista.

39

What are the structures of the Semicircular ducts?

Crista = transversely oriented ridge with hair cells.
Seterocilia in gelatinous mass: cupula

40

Cupola of the semicircular ducts, covers ______ and extends across _______.

- crista
- ampulla

41

Deflection of the cupola in one direction leads to ________.

Increased firing in afferent fibers.

42

Describe how defection of the cupola occurs...

Rotation of semicircular ducts, as rotation begins endolymph lags behind. If movement continues it will catch up and sensation disappears until you stop, and your endolymph doesn't........

43

_____ & _______ receptors detect linear acceleration of the head.

Utricle and Saccule each contain a patch (Macula)
- Utricle = macula is horizontal when head is straight
- Saccule = macula is vertical when head is upright.

44

Utricle detects what specifically?

forward-backward & side to side.

45

Saccule detects what specifically?

Forward-backward & up and down

46

What is the Otolithic membrane?

Gelatinous membrane of the macula
- contains calcium carbonates crystals, otoconia, otoliths that makes this membrane DENSER than endolymph.

47

What is the primary afferent cell body of the vestibular system?

Vestibular (Sacrpas ganglion) internal auditory canal

48

What are the two types Projections of the vestibular system?

Peripheral process: Synaptic ending on hair cells
Central process: most to vestibuli nuclei of rostral medulla, caudal pons.

49

What are the Four vestibular input Nuceli? What is the relationship of the semicircular duct macula with these nuclei?

1. Superior
2. Inferior
3. Medial
4. Lateral
*Each SC duct and macula has its own pattern and termination pattern in these nuclei.

50

Besides the 4 vestibular nuclei, what else provides input to vestibular system?

Cerebellum (Flocculonodular lobe)
spinal cord
contralateral vestibular nuclei

51

Where does lateral Vestibulospinal fibers arise from?

The Lateral Nucleus down lateral funiculus

52

What is the function of the lateral Vestibule spinal tract?

Mediates postural changes to accomodate tilts in the body.

53

Where does Medal VS tract originate from?

Medial nucleus

54

Function of medal VS tract?

Stabilizes head movement as you walk
coordinates head and eye movement

55

What is the VOR and what does it do?

Vesctibuloocular relfex = works to prevent images from moving on the retina.

56

What is Nystagmus?

VOR can't compensate for head movements, interrupted by very rapid eye movements in opposite direction (watching telephone poles out car window)

57

How does does alcohol make the cupola sensitive to gravity?

Normal cupula density = endolymph density
- as blood alcohol increase EtOH infiltrates cupola and density of cupola decrease relative to endolymph and nystagmus results.

58

What is position sense mediated by?

By vestibular, proprioceptive and visual systems all working together to produce sense of orientation and movement. ( if one is defective other two can compensate)

59

What is Romberg's sign?

swaying or loosing balance when eyes are closed.

60

_______ is between Scala tympani & Scala Media.

Basilar membrane

61

__________ is between scala Tympani & Scala vestibuli.

Reissners membrane

62

_____ is spongy bone is surrounding the spiral ganglion..

Modiolus

63

Stimuli for organ of corti is.....

Sound

64

Stimuli for cristae is.....

angular acceleration

65

Stimuli for maculae is...

linear acceleration