Unit Three: Equilibrium and Hearing Flashcards

1
Q

What are the three anatomical regions of the ear?

A
  1. External ear. 2. Middle ear. 3. Internal ear.
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2
Q

What anatomical region of the ear contains the sensory organs for equilibrium (balance) and hearing?

A

The internal ear.

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3
Q

What does the external ear include? (2)

A
  1. The outer fleshy auricle. 2. External acoustic meatus.
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4
Q

What does the auricle protect? What does it provide?

A

The opening passageway and provides directional sensitivity to the ear by directing sound inward toward the tympanic membrane.

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5
Q

What is the tympanic membrane? What does it separate?

A

The eardrum. It is thin, semitransparent connective tissue separating the external ear from the middle ear.

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6
Q

What do ceruminous glands secrete?

A

Cerumen.

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7
Q

What does cerumen do?

A

Slows the growth of microorganisms and reduces the chance of infection.

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8
Q

What are ceruminous glands modifications of?

A

Sweat glands.

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9
Q

What does the middle ear consist of?

A

The tympanic cavity, which contains auditory ossicles.

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10
Q

What is the tympanic cavity?

A

An air-filled space that contains auditory ossicles.

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11
Q

What does the tympanic cavity communicate with? (2)

A

The nasopharaynx through the auditory canal. 2. Mastoid air cells.

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12
Q

Where does the auditory tube penetrate?

A

The petrous part of the temporal bone.

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13
Q

What is the auditory tube also called?

A

Eustachian tube.

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14
Q

What does the auditory tube do?

A

It helps equalize the pressure in the middle ear with external, atmospheric pressure.

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15
Q

What do the three bones comprising the auditory ossicles do?

A

They connect the tympanic membrane with the receptor complex of the internal ear.

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16
Q

What are the three auditory ossicles connected by? What do they do?

A

Synovial joints. They transfer sound vibrations from the tympanic membrane to a fluid-filled chamber within the internal ear.

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17
Q

What are the three auditory ossicles?

A
  1. Malleus. 2. Incus. 3. Stapes.
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18
Q

What is the oval window?

A

A hole in the bony wall of the middle ear cavity.

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19
Q

What does vibration of the tympanic membrane do?

A

It converts arriving sound waves into mechanical movements.

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20
Q

Describe the vibration of the auditory ossicles.

A

The malleus vibrates the incus. The incus vibrates the stapes.

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21
Q

What does the movement of the stapes do?

A

It causes vibrations in the fluid contents of the internal ear.

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22
Q

What is the auricle of the external ear made up of?

A

Elastic cartilage.

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23
Q

What two muscles reduce movements of the auditory ossicles in the ear?

A
  1. Tensor tympani muscle. 2. Stapedius muscle.
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24
Q

What muscle equalizes pressure?

A

Levator veli palatini.

25
Q

What are the two divisions of the inner ear?

A
  1. Bony labyrinth. 2. Membranous labyrinth.
26
Q

What does the bony labyrinth contain?

A

Perilymph.

27
Q

What does the membranous labyrinth contain?

A

Endolymph.

28
Q

Is perilymph and endolymph a byproduct of cerebrospinal fluid?

A

Yes.

29
Q

What are the layers of the inner ear (from outside-in)? (4)

A
  1. Bony labyrinth. 2. Perilymph. 3. Membranous labyrinth. 4. Endolymph.
30
Q

What can the membranous labyrinth be divided into? (2)

A
  1. Cochlear duct (hearing). 2. Vestibular complex (equilibrium).
31
Q

What can the vestibular complex include? (2)

A
  1. Semicircular ducts (rotation). 2. Utricle and saccule (gravity and linear acceleration).
32
Q

Where do high frequency sounds stimulate the spiral organ?

A

More proximal to the oval window.

33
Q

Where do low frequency sounds stimulate the spiral organ?

A

Closer to the apex of the cochlea.

34
Q

What 3 channels are the cochlea divided into?

A
  1. Scala vestibuli. 2. Scala tympani. 3. Cochlear duct.
35
Q

What does the spiral organ detect?

A

Endolymph movement.

36
Q

What is the tectorial membrane?

A

The overlying gelatinous mass the stereocilia project into.

37
Q

Where does the spiral organ sit?

A

On the basement membrane.

38
Q

What do spiral organs contain?

A

Thick sensory epithelium with hair cells.

39
Q

Describe the path of sound waves through the ear (1-4).

A
  1. Tympanic membrane. 2. Auditory ossicles. 3. Oval window. 4. Scala vestibuli.
40
Q

Describe the path of sound waves through the ear from the scala vestibuli (3).

A
  1. Cochlear duct. 2. Scala tympani. 3. Round window.
41
Q

In what Brodmann’s area is the primary auditory cortex?

A

41, 42.

42
Q

Describe the first 3 steps of the CNS pathway of audition.

A
  1. Basilar membane. 2. Cochlear part of CN VIII. 3. Brainstem nuclei (Cochlear nucleus).
43
Q

Describe the second 3 steps of the CNS pathway of audition.

A
  1. Medial geniculate nucleus (thalamus). 2. Primary auditory cortex. 3. Auditory association cortices.
44
Q

What does the utricle allow for?

A

An understanding of horizontal movement.

45
Q

What does the saccule allow for?

A

An understanding of vertical movement.

46
Q

What is the macula of the utricle and saccule?

A

The portion of the above regions that contain hair cells.

47
Q

What are stereocilia and kinocilia embedded in?

A

A gelatinous layer covered in otoliths.

48
Q

What are the three semicircular canals/ducts?

A
  1. Anterior. 2. Posterior. 3. Lateral.
49
Q

What is the ampulla?

A

The expanded region of each semicircular canal.

50
Q

What is the cupula?

A

The overlying gelatinous dome that stereocilia and kinocilia are embedded into.

51
Q

What semicircular duct is sensitive to “yes?”

A

Anterior.

52
Q

What semicircular duct is sensitive to “no?”

A

Lateral.

53
Q

What semicircular duct is sensitive to “tilting head?”

A

Posterior.

54
Q

What happens when the head rotates?

A

The endolymph moves and pushes against the cupula and bends the stereocilia.

55
Q

Describe the CNS pathway for vestibulation (2).

A
  1. Vestibular part of CN VIII. 2. Vestibular nuclei (medulla).
56
Q

What occurs in the CNS pathway for vestibulation once the sensory info reaches the medulla? (2)

A
  1. Integration of sensory info. 2. Info gets relayed to cerebellum, cerebral cortex, spinal cord, CN III, IV, VI, XI.
57
Q

What nerves receive information from the vestibulation pathway? (4)

A
  1. III. 2. IV. 3. VI. 4. XI.
58
Q

Describe the path of where vestibular nuclei relay information (4).

A
  1. Cerebellum. 2. Motor nuclei of the extra-ocular muscle of the eye. 3. Cerebral cortex to provide conscious sens of position and movement. 4. To other motor nuclei in the brainstem and spinal cord.