Lecture 31b Flashcards

1
Q

Three parts of the ear/vestibulocochlear organ

A
  • external ear
  • middle ear
  • internal ear
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2
Q

External ear parts

A
  • auricle/pinna

- external acoustic meatus

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3
Q

Different parts of auricle/pinna

A
  • helix
  • antihelix
  • concha
  • tragus
  • antitragus
  • lobule
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4
Q

In the average adult, how long is the external acoustic meatus?

A

The canal is about an inch long

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5
Q

What directions does the acoustic canal take?

A

inward –> bends backward –> bends forward and down

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6
Q

Where does the external acoustic meatus end?

A

tympanic membrane

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7
Q

How is the acoustic canal divided up?

A
  • outer 1/3 is cartilaginous (secrete cerumen; wider)

- inner 2/3 is bony (NO cerumen; narrower)

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8
Q

Middle ear ossicles

A
  • malleus/”hammer” (most lateral)
  • incus/”anvil”
  • stapes/”stirrup” (most medial)
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9
Q

What is the roof of the middle ear called?

A

tegmen tympani

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10
Q

What space is directly INTERNAL to tympanic membrane?

A

tympanic cavity

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11
Q

What space is directly ABOVE the tympanic membrane?

A

epitympanic recess

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12
Q

What is the tympanic membrane composed of?

A
  • skin
  • mucous membrane
  • connective tissue
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13
Q

Which ossicle is attached to the inner side of the tympanic membrane?

A

malleus

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14
Q

Umbo

A

center-most depressed portion of tympanic membrane

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15
Q

Medial wall of middle ear

A

promontory created by base of the cochlea

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16
Q

Two openings associated with promontory

A
  • fenestra vestibuli (oval; receives footplate of stapes)

- fenestra cochlea (round; closed by membrane)

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17
Q

Anterior to tympanic membrane

A

tympanic cavity (contains tensor tympani)

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18
Q

Tensor tympani has an opening leading to the…

A

eustachian/auditory tube

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19
Q

Eustachian/auditory tube

A
  • connects middle ear and nasopharynx

- 1/3 bony (auditory end) and 2/3 cartilaginous (nasopharyngeal end)

20
Q

Tubal tonsil

A

collection of lymphoid tissue in opening of auditory tube in nasopharynx

21
Q

aditus ad antrum (opening to the mastoid antrum)

A

communicates below and behind tympanic membrane with the mastoid air cells

22
Q

Pyramidal eminence originates with the…

A

stapedius muscle

23
Q

The 3 ossicles are united by ________ and are suspended in air by ____________

A
  • joints

- their attachments to each other, the tympanic membrane, and the oval window

24
Q

Nerves coursing within the ear

A
  • tympanic plexus (from tympanic branch of CN IX)

- chorda tympani branch of CH VII

25
Q

Internal ear most responsible for…

A

essential organs for hearing and sense of balance

26
Q

Organs of the internal ear

A
  • cochlear duct (for hearing)
  • semicircular ducts (for balance and position)
  • utricle (for balance and position)
  • saccule (for balance and position)
27
Q

Organs of the internal ear contain a fluid called…

A

endolymph, which stimulates sensory endings, which stimulates fibers of CN VIII to fire and send info to brain

28
Q

Membranous labyrinth

A
  • composed of semicircular ducts, cochlear duct, utricle, and saccule
  • contained within bony labyrinth
29
Q

Bony labyrinth components

A
  • cochlea (contains cochlear duct)
  • vestibule (contains utricle and saccule)
  • semicircular canals (contains semicircular ducts)
30
Q

Where is perilymph found?

A

between the bony and membranous labyrinth

31
Q

Cupula

A

center of cochlea

32
Q

Osseous spinal lamina

A

along with membranous labyrinth, divides internal cochlea into

  • scala vestibuli
  • scala tympani
33
Q

Round (cochlear) window

A
  • allows expansion of fluid upon vibration
  • covered by a membrane
  • found at base of cochlea
34
Q

Vestibule location

A
  • middle portion of bony labyrinth
  • relates to the cochlea lying anteriorly
  • relates to semicircular canals lying posteriorly
35
Q

Oval (vestibular) window

A
  • opening in lateral vestibular wall

- accommodates the footplate of stapes

36
Q

What do vibrations of the stapes produce?

A

surges in the fluid of the vestibule

37
Q

Three semicircular canals

A
  • anterior canal
  • lateral canal
  • posterior canal
38
Q

Ampulla

A
  • the enlargement where the semicircular canal joins the vestibule
  • it’s through here that the fibers from the vestibular portion of CN VIII pass
39
Q

What lines internal cavity of the bony labyrinth?

A

membranous labyrinth

40
Q

Membranous labyrinth main function

A

convert the mechanical energy of the vibrating fluid to electrical energy that can be carried to the brain via CH VIII

41
Q

What forms the membranous part of the bony trochlea?

A

cochlear duct

42
Q

Cochlear duct is modified into…

A
  • vestibular (Reissner’s) membrane

- basilar membrane

43
Q

Basilar membrane modification

A

spiral organ (of Coti), sensory ending for hearing of CN VIII

44
Q

What forms the membranous part of the bony vestibule?

A
  • utricle

- saccule

45
Q

Utricle and saccule each have a portion of ________, which is responsible for _________

A
  • sensory epithelium

- communicating with vestibular portion of CN VIII for perception of static position sense

46
Q

What is the membranous part of the anterior, posterior, and lateral semicircular canals?

A

semicircular ducts

47
Q

Ampullary crest

A

where the fibers from the vestibular portion of CN VIII pass