Auditory 2 Flashcards Preview

SHB - Exam 3 > Auditory 2 > Flashcards

Flashcards in Auditory 2 Deck (48)
Loading flashcards...
1
Q

What are the 3 systems required for proper balance? (functioning of motor activities, eye movements, & posture)

A
  1. Vestibular System
  2. Visual System (least reliable)
  3. Prioreceptive

-no vestibular = nausea &vomiting ( position of head & body in space)

2
Q

What is within the bony labyrinth? Membranous labyrinth?

A
  1. Perilymph (bony)

2. Endolymph(membranous)

3
Q

What are the 2 otolyphic organs?

A
  1. Utricle (horizontal)

2. Saccule (vertical movement)

4
Q

Where is the vestibular system located in the skull?

A

in the petrous part of the TEMPORAL bone

  • lateral to the internal acoustic meatus (along w/ cochlea)
5
Q

The bony & membranous labyrinths of vestibular system are continuous with the Auditory system: TRUE OR FALSE

  • what fluids are in each?
A

TRUE

  1. Bony = PERILYMPH
  2. Membranous = ENDOLYMPH
6
Q

What are the 3 main divisions of the vestibular system? Which two are otolithic organs? What movement do each serve?

A
  1. Semicircular canals (circular motion)
  2. Utricle - horizontal
  3. Saccule - verticle

UTRICLE & SACCULE are otolithic organs

(semicircular canals just have endolymph)

7
Q

What fluid is essential for the creation of receptor potentials? What are the primary receptors in the Vesitbular (and auditory) system?

A
  1. ENDOLYMPH

2. Hair cells

8
Q

What organ of the vestibular system uses the MLF to coordinate movements of the eye w/ head & neck?

A

SEMICIRCULAR canals

  • use CN 3,4,6
9
Q

Which vestibular organ is the primary gravity & acceleration sensor?

A

UTRICLE

10
Q

Where are the hair cells in the semicircular canals located in? What is the gelatinous substance that covers the hair cells?

A
  1. AMPULLA of the canal (ampulary crest & cupola)

2. CUPOLA

11
Q

If the head moves to the right, which direction does the cupola move? What is this called?

A
  1. Cupola moves LEFT (opposite)

2. INERTIAL DISPLACEMENT of the fluid & cupola - bends hair cells

12
Q

The inertial displacement is an acceleration force or a velocity?

A

ACCELERATION

but considered velocity

13
Q

What occurs when the sterocilium move towards the kinoocilium? AWAY?

A
  1. DEPOLARIZATIOn (K+ in)
  2. HYPERPOLARIZATION
  • K+ influx
  • depolarization
  • calcium released
  • NT released
  • Bipolar cells FIRE AP
14
Q

What fires action potentials, hair cells or bipolar cells?

A

BIPOLAR CELLS

15
Q

The greater the difference in INERTIAL DISPLACEMENT = the greater _____

A

greater perceived “velocity”

actually acceleration, but perceived as velocity

16
Q

If the head is moving counterclockwise, which direction does the fluid on the left & right move in the horizontal canals?

A

LEFT: moves OPPOSITE

  • clockwise (TOWARD KINOCILIUM)
    = increase FIRING!!!

RIGHT: moves counterclockwise
- AWAY from kinocilium = decrease in firing

17
Q

The anterior canal on right is paired with ____ canal on left.
The posterior canal on right is paired with the ____ canal on the left.
Which canals are paired?

A
  1. Posterior canal on left
  2. Anterior canal on left

HORIZONTAL CANALS ARE PAIRED

18
Q

If there is an infection, or if one canal in a specific plane stops working, this is perceived as____

A

MOVEMENT

  • increase in K+
19
Q

What has a tonic output in the vestibular system? As long as this cancels out on both sides, the brain perceives it as NO MOVEMENT

A

vestibular Nerve

so that the decrease or increase in K+ can be sensed by the vestibular system

20
Q

Because the saccule & utricle contain OTOLITHIC granules (calcium carbonate), this allows them to respond to what?

A

GRAVITY

  • granules have weight
21
Q

Where are the auditory hair cells located?

A

Organ of Corti on a thin basilar membrane in the COCHLEA of the inner ear

22
Q

Which organ (SSC, utricle or saccule):

  1. detects upright position & head tilt
  2. is the primary gravity sensor
  3. HORIZONTAL linear acceleration
A

UTRICLE!!!

23
Q

Which organ (SSC, utricle or saccule):

  1. Detects general orienttion
  2. VERTICAL linear acceleration
A

SACCULE

24
Q

Describe the pathway of INPUT TO CNS from the hair cell to the vestibular nuclei:

A
  1. Hair cell
  2. Bipolar Cell (AP!!)
  3. Vestibular GANGLION
  4. CN 8
  5. Vestibular Nuclei
25
Q

There are 2 divisions of the vestibular ganglion, what structures are located superiorly and what is inferior?

A

SUPERIOR:

  • UTRICLE
  • anterior SACCULE
  • horizontal & anterior SSC

INFERIOR:

  • posterior Saccule
  • posterior SSC *****
26
Q

Where is the vestibular nuclei? The cochlear?

A

Vestibular is medial to ICP

  • Cochlea is the saddle bag of ICP
27
Q

How many vestibular nuclei are there?

A

4

28
Q

Which fibers of the MLF (ascending/descending) control eye movements? Head and neck movements?

A

eye = ASCENDING MLF

head & neck = DESCENDING MLF

29
Q

Which nuclei projects to the cerebellum & coordinates balance with voluntary movement?

A

INFERIOR Nuclei

30
Q

What two structures is the vestibulocerebellum associated with? Where does it receive DIRECT input from?Indirect?

A
  1. Flocculondular lobe
  2. Vestibular nuclei
  • from SCC, utricle & saccule (direct = IMMEDIATE RESPONSE)
  • indirect = Vestibular nuclei, Lateral Geniculat, Superior Colliculus, pontine nuclei
31
Q

Output of the cerebellar influences is projected back to what?

A

VESTIBULAR NUCLEI

  • control axial & proximal limb muscles for BALANCE & POSTURE
  • eye movement, head & neck

(vestibular to cerebellum & then cerebellum back to vestibular)

32
Q

The Lateral Vestibulospinal Tract originates from what nucleus? Where does it project to? Which muscles?

A
  1. LATERAL VESTIBULAR NUCLEUS
  2. ENTIRE LENGTH OF CORD (ventral funiculus)!!!!
  3. PROXIMAL LIMB MUSCLES (extensors)
33
Q

The MEDIAL Vestibulospinal Tract (DESCENDING MLF) originates from what nucleus? Where does it project to? Which muscles?

A
  1. Medial Vestibular Nucleus
  2. CERVICAL SPINAL CORD ONLY!!!!!!
  3. NECK MUSCLES!
    (makes sense to only be cervical spinal cord)
34
Q

What are the 2 primary afferent pathways of the Vestibular system?

A
  1. Vestibular Nuclei

2. Floccolondular lobe

35
Q

What are the 4 SECONDARY Vestibular connections of the Vestibular system?

A
  1. Cerebellum
  2. Spinal cord
  3. Brainstem (ascending MLF, RT)
  4. Thalamic & Cortical
36
Q

What are the 5 types of eye movements?

A
  1. Vestibulo-occular reflex
  2. Optokinetic response (nystagmus)
  3. Smooth pursuit
  4. Saccadic eye movement
  5. Mergence Eye movement
37
Q

What is the RAPID, CATCH UP eye movement called? Is it reflexive?

A

SACCADIC

  • yes, reflexive and PRE-PROGRAMMED
38
Q

What is the voluntary eye movement requiring a moving stimulus?

A

SMOOTH PURSUIT

39
Q

What is vergence?

A

Eyes converge on near objects, diverge on far objects

40
Q

Which eye movement requires the visual/cerebral cortex?

A

SMOOTH PURSUIT (because it is voluntary***)

41
Q

What type of movement stabilizes the image on the retina during rotation of head?

A

VOR

  • Vestibulo-occular

(VOR rotates opposite to the side the head is rotating)

42
Q

How does the visual system attenuate?

A

through the Vestibule-Ocular Reflex ***

-tonic activation via nuclei of 3rd and 6th nerve

43
Q

If the head is moving to the RIGHT, and both eyes begin to move left what occurs in the VOR reflex?

A
  1. Head right
  2. Right horizontal canal activated
  3. RIGHT vestibular nucleus
  4. LEFT 6th nucleus (lateral rectus on left)
  5. RIGHT 3rd nucleus contract the RIGHT medial rectus
  6. BOTH EYES MOVE LEFT
44
Q

What is nystagmus? How is it tested clinically?

A

rhythmic back & forth movement of the eyes
- SMOOTH & SACCADIC movement

  • tested by the caloric test; COWS
    Cold water = nystagmus OPPOSITE
    WARM = same side
45
Q

How do we get dizzy:
1. spinning with eyes closed & suddenly open eyes
(copula returns to baseline )

  1. Looking out a car window when an adjacent car moves away
  2. in the cabin of a boat during a storm (motion sickness)
    - looking at the horizon to minimize this affect
A
  1. Vestibular input w/o vision
  2. Sense of motion through visual system w/o VESTIBULAR CONFIRMATION
  3. Sense of motion through visual system w/o VISUAL confirmation
46
Q

A virus invades the stria vascularis cells of the left inner ear, resulting in a significant increase in the concentration of potassium in the endolymph. Which one of the following would you expect to happen?

a) The outer hair cells hyperpolarize, causing a high pitched “ringing” in the ears.
b) The patient complains of muffled sounds due to smaller receptor potentials in the inner hair cells.
c) The hair cells in the left ampulae depolarize to a greater extent than those on the right, and the patient complains of vertigo/dizziness.
d) The otoconia hyperpolarize, and the patient feels “light-headed.”

A

c)The hair cells in the left ampulae depolarize to a greater extent than those on the right, and the patient complains of vertigo/dizziness.

47
Q

When you voluntarily turn your head to the left, which one of the following events will occur in the vestibular system?

a) Kinocilia in the ampullae of all the semicircular canals will be simultaneously activated.
b) Movement of the stereocilia in the left horizontal canal move towards the kinocilia, resulting in depolarization of the hair cell.
c) The medial and superior vestibular nuclei will be inhibited by the afferent fibers from the semicircular canals.
d) The velocity of the movement is detected by the otolithic granules in the anterior and posterior semicircular canals.
e) Compensatory eye movements will likely be inhibited by the descending MLF.

A

b) b) Movement of the stereocilia in the left horizontal canal move towards the kinocilia, resulting in depolarization of the hair cell.

48
Q

Vestibular function is tested in a 19-year-old man using the caloric test. Assuming a normal outcome, which one of the following is most likely to occur when WARM water is introduced into the man’s RIGHT ear?

a) Horizontal nystagmus, fast phase directed left.
b) Horizontal nystagmus, fast phase directed right.
c) Occular counter-roll (eversion of eyeball) to the right.
d) Vertical nystagmus, fast phase directed downward.
e) Vertical nystagmus, alternating fast phases.

A

COWS

b) Horizontal nystagmus, fast phase directed right.