Ear Flashcards

1
Q

2 main functions of ear

A

equilibrium (balance) - vestibular system

hearing - cochlear system

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2
Q

external ear (pinna/auricle) structures

A
helix
antihelix
antitragus
lobule (no cartilage)
external acoustic meatus
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3
Q

external ear injury

A

Bleeding within the auricle resulting from trauma –> auricular hematoma

compromises blood supply to the cartilage. If untreated (by aspiration of blood) –> fibrosis –> deformed auricle (the cauliflower ear)

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4
Q

sensory innervation of external ear

A

auriculotemporal n. (V3): anterior helix, tragus

lesser occipital n. (C2)

greater auricular n. (C2, C3)

also CN VII and X (small contribution, overlap)

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5
Q

Arnold’s reflex

A

cough reflex initiated by stimulating CN X around external ear

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6
Q

auricular m.

A

superior auricular m.
anterior auricular m.
posterior auricular m.

supplied by motor br. CN VII (temporal br., posterior auricular br.)

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7
Q

blood supply to external ear

A

superficial temporal a.
posterior auricular a.

deep auricular a. –> pt of external acoustic meatus

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8
Q

venous drainage of external ear

superficial temporal v. –> __________

A

superficial temporal v. –> RETROMANDIBULAR V.

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9
Q

venous drainage of external ear

posterior auricular v. –> __________

A

posterior auricular v. –> EJV

posterior auricular + posterior retromandibular –> EJV

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10
Q

lymphatic drainage of lateral top half of external ear

A

to superficial parotid nodes

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11
Q

lymphatic drainage of medial top half of external ear

A

to mastoid nodes

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12
Q

lymphatic drainage of bottom of external ear

A

to superficial cervical nodes

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13
Q

external acoustic meatus has both a _____ and _____ portion

lined with skin containing which types of glands?

A

external acoustic meatus has both a CARTILAGINOUS and BONY portion

lined with skin containing SUBACEOUS and CERUMINOUS glands

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14
Q

tympanic membrane

A

separates external and middle ear

set in sulcus of temporal bone

oriented laterally, anteriorly, and inferiorly

captures changes in air pressure (sound) and transfers to bones of middle ear

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15
Q

otoscopic examination

A

Pull helix posterosuperiorly to straighten external acoustic meatus to view …

  • tympanic membrane
  • lateral process of malleus
  • umbo (handle/manubrium of the malleus poking into the pars tensa)
  • pars flaccida
  • light reflex triangle radiates anteroinferiorly.
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16
Q

sensory innervation to lateral (external) surface of tympanic membrane

A

CN V3, VII, X

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17
Q

sensory innervation to medial surface of tympanic membrane

A

CN IX

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18
Q

sensory fibers from CN IX get to inner surface of ear via the

A

tympanic n. of Jacobsen

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19
Q

tegmen tympani

A

roof over middle ear

separates cranial and tympanic cavities

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20
Q

arcuate eminence

A

elevated area on petrous portion of temporal bone

overlays semicircular canals

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21
Q

middle ear bones (ossicles)

A

malleus

incus

stapes

(all 3 function in conduction of sound thru middle ear)

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22
Q

posterior process on head of malleus articulates w/ body of ____

A

posterior process on head of malleus articulates w/ body of INCUS

(ice cream scoop + cone)

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23
Q

tensor tympani m.

innervation/origin/insertion

A

V3

tendon inserts onto handle of malleus

originates off cartilaginous portion of pharyngotympanic tube and part of the sphenoid GW

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24
Q

lenticular process of incus articulates w/ ____

A

lenticular process of incus articulates w/ STAPES M.

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25
Q

stapedius

innervation/origin/insertion

A

CN VII

tendon inserts onto neck of stapes

originates off walls of pyramidal eminence

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26
Q

paralysis of stapes

A

xs acuteness of hearing (hyperacusis)

poss due to CN VII lesion

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27
Q

middle ear blood supply

A

anterior tympanic a. (off 1st pt. maxillary a.)

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28
Q

middle ear lymphatic drainage

A

superior deep cervical nodes

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29
Q

middle ear innervation

A

CN IX (sensory to INNER surface tympanic membrane)

some CN V, IX, X (rest of middle ear)

parasympathetic (CN VII)

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30
Q

membranous wall of middle ear

A

lateral

  • tympanic membrane
  • chorda tympani, passes over tensor tympani m.
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31
Q

segmental wall of middle ear

A

superior

  • tegmen tympani
  • epitympanic area
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32
Q

labyrinthine wall of middle ear

A

medial

  • lateral semi-circular canal
  • facial canal
  • processus cochleariformis
  • oval window (fenestra vestibuli)
  • promontory
  • round window (fenestra cochlea)
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33
Q

oval window

A

communication between middle and inner ear (into scala vestibuli of the cochlea)

base of stapes inserts onto here

on labyrinthine wall

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34
Q

promontory

A

right below oval window, on labyrinthine wall

1st basal turn of cochlea that bulges out into middle ear

has tympanic plexus (where tympanic n. of Jacobsen comes thru)

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35
Q

round window

A

secondary tympanic membrane, on labyrinthine wall
(blocked from scala tympani by a membrane)

alleviates pressure from oval window and stapes (oval membrane moves in –> round window moves out –> fluid moves into cochlea –> moves inner hair cells –> hearing)

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36
Q

jugular wall of middle ear

A

inferior

- jugular fossa (IJV runs past)

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37
Q

mastoid wall of middle ear

A

posterior

  • facial n. runs thru
  • aditus
  • pyramidal eminence (encloses stapedius m.)
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38
Q

aditus

A

opening from middle ear to mastoid air cells

39
Q

carotid wall of middle ear

A

anterior wall

  • carotid canal (internal carotid a. travels right in front of this wall)
  • opening of pharyngotympanic tube (Eustachian tube)
  • semi-canal for tensor tympani
40
Q

processus cochleariformis

A

tensor tympani m. makes a turn around this

41
Q

contraction of which m. open the pharyngotympanic tube to equalize pressure?

A

tensor and levator veli palatini

^also involved in draining middle ear

42
Q

otitis media

A
  • infection of middle ear
  • bulging, red tympanic membrane and visible air-fluid meniscus behind it
  • may block Eustachian tube due to mucosal inflammation
  • untreated –> scars ossicles –> hearing loss
43
Q

mastoiditis

A

infections travel thru aditus into mastoid air cells

  • especially in children, otitis media spreads superiorly thru petrotympanic fissure causing osteomyelitis of tegmen tympani (roof of middle ear)
44
Q

1st arch ear structures

A

malleus
incus
tensor tympani

45
Q

2nd arch ear structures

A

stapes

stapedius

46
Q

1st cleft ear structures

A

external acoustic meatus

47
Q

1st pouch ear structures

A

pharyngotympanic tube

middle ear cavity

48
Q

otic placode ear structures

A

membranous labyrinth in inner ear

49
Q

tympanic membrane forms where during development?

A

at interface of 1st pouch and 1st cleft

50
Q

cochlea contains which ganglion

A

spiral ganglion (DRG equivalent for CN VIII)

51
Q

labyrinthine a.

A
  • off the anterior inferior cerebellar a.

- travels thru internal acoustic meatus to supply INNER ear

52
Q

canals within the inner ear form the _______ labyrinth

A

canals within the inner ear form the BONY labyrinth (fluid-filled, perilymph)

53
Q

membranous labyrinth

A

membrane enclosed space within the bony labyrinth

suspended by delicate filaments

fluid-filled, endolymph

2 parts: vestibular labyrinth, and cochlear labyrinth

54
Q

endolymphatic duct

A

from endolymphatic sac, fills up all parts of membranous labyrinth with endolymphatic fluid

55
Q

perilymphatic space is connected to the _________ which is continuous w/ the subarachnoid space

A

perilymphatic space is connected to the COCHLEAR AQUEDUCT which is continuous w/ the subarachnoid space

perilymph resembles extracellular fluid in composition (sodium salts are the predominate positive electrolyte) and, via the perilymphatic duct, is in continuity with CSF.

56
Q

endolymph function is important for function of inner ear, how?

A

if pressure of endolymph too great, or if ionic concentration is off –> hair cells can’t move –> tinnitus, hearing loss, vertigo

57
Q

Meniere’s syndrome

A

xs endolymph production or blockage of endolymphatic duct

–> recurrent tinnitus, hearing loss, vertigo

58
Q

tiny hole just below internal acoustic meatus

A

for cochlear aqueduct

continuous w/ subarachnoid space

59
Q

what is the sliver shape on ridge of bone, just above sigmoid sinus?

A

vestibular aqueduct

conveys endolymphatic duct (conveys endolymphatic fluid thru temporal bone)

there will be little pouch just underneath the dura for this

60
Q

vestibular labyrinth

A

semicircular ducts

utricle

saccule

61
Q

utricle and saccule

A
  • contain hair cells sensitive to gravity and linear movement of head
  • hair cells concentrated in areas called maculae
  • hair cells embedded in jelly containing otoliths (statoconia) which pulls jelly in direction of gravity
  • sensitive to movement in same plane as macula
62
Q

utricle macula

A

horizontal plane

63
Q

saccule macula

A

vertical plane

64
Q

semicircular ducts

A

anterior, posterior, and lateral duct

sensitive to ROTATIONAL MOVEMENT of head

hair cells concentrated in ampullary crest (CRISTA) within the ampulla

within cristae, hair cells embedded in cupula (gelatinous)

movement of fluid across cupola –> depolarization of hair cells, signals along vestibular nerve

65
Q

balance and positional awareness are integrations of which systems

A

vestibular and visual systems

66
Q

anterior (superior) semicircular duct

A

responsive to nodding head yes

67
Q

lateral (horizontal) semicircular duct

A

responsive to shaking head no

68
Q

posterior semicircular duct

A

responsive to cartwheels, more angular rotation

69
Q

motion sickness

A
  • Maculae of membranous labyrinth are static organs, filled with otoliths which bend the hair cells to stimulate the vestibular nerve providing motion awareness.
  • If the vestibular stimulation is disproportionate or there is discordance between visual input and vestibular input, motion sickness results.

(stopped turning, but have sensation of turning in opp direction as moving fluid directs hairs in opp direction)

70
Q

modiolus

A

inner core of bone in cochlea which houses spiral ganglion

71
Q

cochlear duct contains

A

endolymph

72
Q

scala vestibuli and scala tympani contain ____ fluid

A

scala vestibuli and scala tympani contain PERILYMPH fluid

73
Q

mechanical energy transmitted through the oval window causes vibrations within fluids of _________

A

mechanical energy transmitted through the oval window causes vibrations within fluids of COCHLEA

74
Q

organ of corti

A

senses vibrations within fluids of the cochlea that were transmitted through the oval window

75
Q

inner hair cells of cochlear system

A
  • afferent innervation

- stereocilia in endolymph

76
Q

outer hair cells of cochlear system

A
  • afferent and efferent innervation

- stereocilia embedded in tectorial membrane

77
Q

basilar membrane

A

resonant structure

dif parts of membrane have dif physical properties

regions of the basilar membrane vibrate in response to certain frequencies

movement of membrane bends sterocilia

78
Q

sensorineural hearing loss

A
  • defects or damage to cochlea or cochlear n.

cochlear nuclei info –> primary auditory cortex

79
Q

presbycusis and high tone hearing loss

A

aging and persistent exposure to excessively loud sounds

inner hair cells at basal end= most susceptible to damage

difficulty hearing consonants (s, f, h, th, k, p), or in loud situations

80
Q

conductive hearing loss

A

loss of sound conduction from external or middle ear

impaired movement of oval or round window

cochlear implant

81
Q

processus cochleariformis

A

bump where medial wall of middle ear joins w/ anterior wall, forms fulcrum for tensor tympani m. as it comes across middle ear

82
Q

pyramidal eminence

A

small projection on mastoid wall of inner ear

encloses STAPEDIUS m.

83
Q

the ___ bone transmits movement to the oval window

A

the STAPES bone transmits movement to the oval window

84
Q

Locating bony opening of pharyngotympanic tube at base of skull

A

just posterior to foramen ovale and foramen spinosum, look for groove with a hole

the entrance to the bony canal is found between foramen spinosum and carotid canal

85
Q

pharyngotympanic tube is easily blocked by swelling of…

A

its mucosal membrane

86
Q

each semicircular duct has an expanded part at the lateral end, called the ampulla, where it joins the _____

A

utricle

87
Q

utriculosaccular duct

A
  • part of the membranous labyrinth of the inner ear
  • connects 2 parts of the vestibule, the utricle and the saccule
  • continues to the endolymphatic duct and ends in the endolymphatic sac
88
Q

ductus reuniens

A

connects the lower part of the saccule to the cochlear duct

89
Q

tectorial membrane

A

gelatinous membrane, stereocilia embedded within

90
Q

scala media

A

cochlear duct

91
Q

____ hair cells act as cochlear acoustic amplifiers

A

OUTER hair cells act as cochlear acoustic amplifiers

92
Q

describe the 2 ends of the basilar membrane

A

basal end (narrow, stiff, HIGH pitch sounds)

apical end (wide, floppy, responsive to LOW sounds)

93
Q

the cartilaginous part of the Eustachian tube opens into the

A

nasal pharynx