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Flashcards in Auditory 1 Deck (57)
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1
Q

Which two systems in the ear are interconnected?

A

Vestibular & Cochlear

2
Q

Where does the stapes sit?

A

On the oval window

3
Q

What is the function of the round window?

A

Pressure release valve

-round window & oval window move in opposite directions

4
Q

What is the mechanical portion to push the fluid in the ear?What is made of?

A

OSSICLES

  • BONE
5
Q

How is sound produced?

A

Sound is produced by vibrations

- cause the alternating compression and decompression of the surrounding air

6
Q

What happens if the information traveling in the sound wave is interrupted before it reaches the Cerebral cortex?

A

IT NEVER HAPPENED

7
Q

What are the receptors of sound?

A

Hair cells, which are sensitive to movement

8
Q

What hertz levels can humans perceive?

A

10-20,00 Hz

9
Q

What membrane does air vibrate? What gets lifted up and down?

A

Tympanic Membrane

  • Malleus is lifted up & down
10
Q

What muscle equalizes air pressure in the ear? What innervates this muscle

A

Tensor Tympani

  • CN V3
11
Q

Where in the ear is the air pressure (sound waves) converted to mechanical energy? Which two structures are responsible for this?

A
  1. MIDDLE EAR
  2. Tympanic Membrane
  3. Ossicles
12
Q

How does the middle ear communicate with the nasopharynx? (lies medial to the tympanic membrane..

A

AUDITORY TUBES (eustachian tube)

13
Q

What is the site of chronic infections, Otitis Media?

A

AUDITORY TUBE

14
Q

What forms the roof of the middle ear?

A

Temporal Bone

–> MIDDLE CRANIAL FOSSA

15
Q

What 2 nerves travel through the middle ear cavity?

A

CN 7 & CN 9 (Tympanic Nerve)

16
Q

What muscle helps attenuate sound? What cranial nerve innervates this muscle?

A

STAPEDIUS

CN 7

(for loud explosive sound)

17
Q

What is the condition that makes sound be perceived as being louder?

A

Hyperacussis

  • injury to Facial Nerve(7) such as Bell’s Palsy would paralyze Stapedius = cannot dampen sound
18
Q

What is the black shadow found in the tympanic membrane?

A

Chorda Tympani nerve

19
Q

Which 2 nerves are the only visible nerves during exam?

A

CN 7 (chorda tympani)

& CN 2 in the eye?

20
Q

What is the inner ear composed of? Which portion is filled with perilymph? Endolymph?

A
  1. Bony Labyrinth = Perylymph
  2. Membranous labyrinth = Endolymph

(continuous with structures in vestibular system –> Semicircular Canals)

21
Q

What contributes to the formation of the receptor potentials? Is it greater in potassium or sodium?

A

ENDOLYMPH

  • greater in potassium
22
Q

The oval window and round window are continuous in the Membranous Labyrinth. True or False?

A

FALSE

  • they are continuous in the BONY LABYRINTH
23
Q

What are the 3 ways are can be transducer? Which is MOST EFFICIENT?

A
  1. Air = poor conduct
  2. Osseus
  3. Ossicular (Air Conduction)

OSSICULAR IS MOST EFFICIENT*

24
Q

What nerve enters the ear as 1 and splits into 2?

A

Vestibulocochlear -splits into Vestibular N. & Cochlear N

25
Q

Once the cochlea nerve enters the spiral, what is it called?

A

MODIOLUS

26
Q

What is the “hearing” structure? Where is it contained?

A

COCHLEA

  • in the modiolus
27
Q

What are the 3 structures of the cochlea? Which is the oval window, apex, and round window?

A
  1. Scala Vestibuli = Oval Window
  2. Helicotrema =apex
  3. Scala Tympani = Round Window
28
Q

What are the 2 membranes in the cochlea? Which of these membranes does the Organ of Corti sit on?

A
  1. Basilar & Reisner’s

2. Organ of Corti sits on the BASILAR membrane

29
Q

Where does the cochlear duct lie between? What membrane is above? Below?

A

Scala Vestibuli & Scala Tympani

  • REISNERS = above
  • Basilar = below
30
Q

The Reisner’s membrane -s part of scala ____ and the Basilar membrane is part of Scala ______

A
  1. Reisner’s = VESTIBULI

2. Basilar = TYMPANI

31
Q

The Basilar membrane is widest where?

A

widest at HELICOTREMA –> LOW pitch (hell)

narrow –> apex –> OVAL WINDOW
(break the window = high pitch)

(stiffest at the base)

32
Q

Where are high pitches localized? Low?

A

high = near BASE where it is stiffest –> OVAL WINDOW

low = Apex where most flexible –> HELICOTREMA

(think guitar cords)

33
Q

Loudness depends on what?

A

the number of action potentials

34
Q

What important structure sits on the Basilar membrane? What takes place here?

A

ORGAN OF CORTI

  • transduction of pressure waves takes place
35
Q

What is the function of the outer hair cells & the inner hair cells? Which receive more innervation from the Cochlea?

A
  1. OUTER (3 rows)
  • 10% of overall innervation of cochlea
  • DISPLACEMENT sensitive
    2. Inner (1 row)
  • 90% of overall innervation
  • DETECT SOUND, VELOCITY SENSITIVE
36
Q

Which are the only receptors which can be modified by CNS to change the length and stiffness, out or inner hair cells?

A

OUTER hair cells

inner cannot be modified by CNS

37
Q

Which hair cells have more movement?

A

Outer = DISPLACEMENT sensitive

38
Q

What opens the K+ channels in the hairs, causing depolarization?

A

BENING OF HAIR CELLS TOWARDS the Kinocilium

39
Q

Bending AWAY from the Kinocilium results in what?

A

CLOSURE of K+ channels
& hyper polarization of hair cells

  • decrease Neurotransmitter release
40
Q

Where are the action potentials of the ear located?

A

BIPOLAR cells

  • similar to the eye
41
Q

What is the reason for the tonotopic map?

A

difference in stiffness & width of the BASILAR membrane

  • map = perception of different sounds & frequencies

(high = base - narrow & stiff, low = apex - wide & floppy)

42
Q

Where does the tonotopic map travel through?

A
  1. COchlear Nuclei
    - Superior Olivary Nucleus
    - trapezoid body
    - LATERAL LEMNISCUS
  2. Inferior Colliculi
  3. Medial Geniculate
  4. Cerebral Cortex (Herchel’s gyrus)
43
Q

Is the auditory system bilateral or unilateral?

A

BILATERAL

  • unless there is a lesion in 8 or cochlear nuclei–> person will not be deaf
44
Q

What can cause deafness?

A

Lesion in 8 or in Cochlear nuclei

45
Q

Where is Heschel’s gyrus? What is it responsible for?

A

TEMPORAL LOBE - AREA 41

  • Auditory
46
Q

What will result if one cuts the DCN or AVCN (Dorsal Cochlear N. or Anterior Ventral Cochlear Nuclei)

A

Unilateral deafness

past the nuclei - hearing is BILATERAL

47
Q

Which is medial and which is lateral to ICP:
COchlear Nuclei
Vestibular Nuclei

A

Cochlear = LATERAL

Vestibular = Medial

48
Q

How is hearing transmitted to the cortex?

A
  1. Cochlea
  2. Inferior Colliculus
  3. Medial Geniculate
  4. Cortex
49
Q

What is achieved by PHASE LOCKING the hair cells & bipolar cells?

A

TEMPORAL RESOLUTION

50
Q

What happens at the onset of Temporal Resolution and at the offset?

A
  1. fire Action Potentials at the initiation of sound
  2. hyperpolarize offset

push & pull back (rebound)

51
Q

What is the term for the 50 microsecond delay between one ear and another?

A

Interaural Difference

52
Q

What is the auditory region of the cortex? Which lobe is it found in?

A

Herchel’s Gyrus

- Temporal Lobe

53
Q
  1. What is Wiernecke’s Area responsible for?

2. Broca’s?

A
  1. COMPREHENSION

2. Motor (speech output)

54
Q

What is the pre-motor speech pathway in the brain? What two areas does it connect?

A

Arcuate Fasciculus

Connects Wiernecke’s area to Broca’s area

55
Q

Damage to which area will cause a loss in understanding of VISUAL and SPOKEN language?

A

Wiernicke’s Area

56
Q

Damage to which Area will cause a disruption in speech output & verbal production of language?

A

BROCA’s area

57
Q

Lesions to what two areas can affect verbal output?

A
  1. Arcuate Fasciculus

2. Broca’s Area