13-3: Ear Anatomy Flashcards

1
Q

outer ear

A

designed to collect soundwaves and direct them inwards, consists of auricle/pinna, external acoustic meatus, and tympanic membrane

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2
Q

auricle

A

flap of elastic cartilage shaped like a funnel, covered with skin and attached to the head by ligaments and muscles; collects sound waves and funnels them into the ear

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3
Q

external acoustic meatus

A

one inch tube in the temporal bone, from the auricle to the eardrum. The skin lining this bony tube has hairs and ceruminous glands that secrete earwax

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4
Q

What is the function of the external acoustic meatus?

A

keeps dirt, bugs and small objects out of ear and protects the ear drum.

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5
Q

tympanic membrane

A

aka eardrum; thin connective tissue partition separates the outer and middle ear (appears shiny white); vibrates when soundwaves hit it, causing bones in middle ear to move

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6
Q

middle ear

A

small air-filled cavity in the temporal bone. Separated from outer ear by tympanic membrane and from inner ear by a thin bony wall with two windows

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7
Q

eustacian tube

A

connects the middle ear to the nasopharynx; infections often travel from the nose and throat to middle ear through this tube

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8
Q

What is the function of the eustacian tube?

A

equalizes air pressure on both sides of eardrum, preventing it from rupturing - opens when swallowing or yawning

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9
Q

ossicles

A

3 tiny bones extending across middle ear, named for shape

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10
Q

literally “hammer”

A

malleus - attached to inner surface of eardrum

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11
Q

literally “anvil”

A

incus - in the middle

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12
Q

literally “stirrup”

A

stapes - fits into oval window in the bony wall between the middle and inner ear

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13
Q

inner ear

A

aka labyrinth - consists of two parts: bony labrynth and membranous labyrinth

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14
Q

bony labyrinth

A

series of cavities in the temporal bone, filled with perilymph. Consists of vestibule, cochlea, and semicircular canals

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15
Q

vestibule

A

central, egg shaped cavity of inner ear, contains oval window

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16
Q

cochlea

A

anterior to the vestibule, bony spiral resembles a snail shell

17
Q

semicircular canals

A

3 bony canals projecting up and back from the vestibule; at right angles to each other.

18
Q

ampulla

A

swelling at the end of each semicircular canal, has receptors for equilibrium and balance

19
Q

membranous labyrinth

A

interconnecting sacs and ducts inside bony labyrinth. Suspending in perilymph, but filled with endolymph

20
Q

utricle and saccule

A

sacs suspended within the vestibule

21
Q

semicircular ducts

A

line the canals, connect to the utricle

22
Q

What are the three channels within the cochlea?

A

scala vestibuli, scala tympani, cochlear duct

23
Q

The external and middle ear are filled with ___; the bony labyrinth with ___; the membranous labyrinth with ___.

A

air; perilymph; endolymph

24
Q

scala vestibuli

A

upper, bony channel, filled with perilymph. Connects with the oval window

25
Q

scala tympani

A

lower, bony channel, filled with perilymph; ends at the round window

26
Q

cochlear duct

A

membranous channel between the other 2, filled with endolymph

27
Q

The cochlear duct is separated from the scala vestibuli by the ___ and the scala tympani by the ___.

A

vestibular membrane; basilar membrane

28
Q

organ of corti

A

organ of hearing - located on the inner surface of the basilar membrane in the cochlear duct.

29
Q

stereocilia

A

auditory receptors lining organ of corti

30
Q

The free ends of the hair cells in the organ of ___ extend into the ___ of the cochlear duct, and are covered by ____.

A

corti; endolymph; tectorial membrane

31
Q

The base of hair cells connect to neurons of the cochlear branch of cranial nerve ___ (aka ____)

A

VIII; vestibulocochlear

32
Q

labyrinthitis

A

inflammation of inner ear