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A&P I > Exam 7 - Ear > Flashcards

Exam 7 - Ear Flashcards

1
Q

The ear is divided into three main regions:

A

External ear, which collects sound waves and funnels them inward

Middle ear, which conveys sound vibrations to the oval window

Internal (inner) ear, which contains the receptors for hearing and for equilibrium

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2
Q

which collects sound waves and funnels them inward

A

External ear

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3
Q

which conveys sound vibrations to the oval window

A

Middle ear

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4
Q

which contains the receptors for hearing and for equilibrium

A

Internal (inner) ear

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5
Q

The external ear consists of the

A

Auricle
External auditory canal
Eardrum

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6
Q

The rim of the auricle is the

A

helix

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7
Q

The inferior portion is the

A

lobule

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8
Q

________ lies in the temporal bone, and leads to the eardrum

A

The external auditory canal

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9
Q

The eardrum has a covering of

A

epidermis

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10
Q

___ ____ are specialized sebaceous (oil) glands that secrete earwax (cerumen), which in combination with hairs that are present helps prevent dust and foreign objects from entering the ear

A

Ceruminous glands

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11
Q

The ___ is a small pointed eminence projecting backward over the meatus

A

tragus

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12
Q

The ____ is opposite the tragus

A

antitragus

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13
Q

Regionally are the mastoid process posterior to the lobule, and the __ __ __ anterior to the tragus

A

superficial temporal artery

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14
Q

The middle ear is a small air-filled cavity in the…

A

…temporal bone

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15
Q

The middle ear

It is separated from the external ear by the eardrum, and from…

A

the inner ear by the oval window and the round window

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16
Q

WHERE IS THE SITE OF TRANSDUCTION FROM LECTURE 1 ????

A

HE said it was important in lecture so I threw it in here as a reminder… find the answer in JB’s cards

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17
Q

The middle ear contains the ____ ____ :

They transmit vibratory motions of the eardrum to the oval window

A

auditory ossicles

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18
Q

The ossicles are named for their shapes:

A

Malleus (hammer)
Incus (anvil)
Stapes (stirrup)

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19
Q

(hammer)

A

Malleus

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20
Q

(anvil)

A

Incus

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21
Q

(stirrup)

A

Stapes

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22
Q

Auditory ossicles:

The handle of the ____ is secured to the internal surface of the eardrum

The incus articulates with the….

The base of the stapes fits into the __ ___

A

malleus

…malleus laterally and the stapes medially

oval window

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23
Q

The handle of the malleus is secured to the…

A

… internal surface of the eardrum

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24
Q

The incus articulates with the ___ laterally and the ____ medially

A

malleus laterally and the stapes medially

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25
Q

The base of the ___ fits into the oval window

A

stapes

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26
Q

What can be seen on the tympanic membrane with an otoscope?

A

The handle and lateral process of the malleus, and the long limb of the incus produce bulges that can be seen when viewing the tympanic membrane using an otoscope

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27
Q

Muscles of the middle ear

Two small skeletal muscles attach to the ossicles:

A

Tensor tympani muscle

Stapedius muscle

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28
Q

Tensor tympani muscle

Arises from the wall of the auditory tube and inserts into….

Limits movement and increases tension on the eardrum to….

Innervated by…

A

….the handle of the malleus

prevent damage from loud noises

…. the trigeminal nerve (V)

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29
Q

Stapedius muscle

Originates from ?

Dampens ?

Innervated by ?

____ skeletal muscle in the body

A

Originates from the posterior wall of the middle ear cavity and inserts into the stapes

Dampens large vibrations of the stapes due to loud noises

Innervated by the facial nerve (VII)

Smallest skeletal muscle in the body

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30
Q

slide 13 otoscopic view

A

slide 13 otoscopic view

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31
Q

slide 14

A

slide 14

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32
Q

An ear exam includes bilateral otoscopic inspection of both tympanic membranes. A normal tympanic membrane is

A

pearly gray and translucent

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33
Q

The cone of light is a reflection from the otoscope’s illuminator. Termed the __ __, it is visible radiating ____ in a healthy ear, and can provide orientation

A

light reflex

anteroinferiorly

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34
Q

Also called the auditory tube, or the pharyngotympanic tube

Consists of both bone and cartilage

Connects the middle ear with the nasopharynx

A

Eustachian tube

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35
Q

Eustachian tube

Also called the ?

Consists of?

Connects the middle ear with the ?

A

Also called the auditory tube, or the pharyngotympanic tube

Consists of both bone and cartilage

Connects the middle ear with the nasopharynx

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36
Q

It is normally closed, but opens upon swallowing and yawning

Equalizes the pressure in the middle ear with the atmosphere

Without equalization, the ear would not be as effective, and pain or vertigo could also develop

A

Eustachian tube

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37
Q

The Eustachian tube is also a route that pathogens may take from the…

A

…nose and throat to the middle ear

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38
Q

The inner ear is also called the…

Two main divisions?

A

…labyrinth

Bony labyrinth (outer) 
Membranous labyrinth (inner
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39
Q

The bony labyrinth is a series of cavities in the petrous portion of the temporal bone comprising three areas

A

Semicircular canals
Vestibule
Cochlea

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40
Q

The ___ ___ is a series of sacs and tubes inside the bony labyrinth, which has the same general form as the bony labyrinth

A

membranous labyrinth

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41
Q

Cross-sectional representation of semicircular canal and contained semicircular duct

A

slide 21 of membranosu labryrinth

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42
Q

Fluids in the inner ear?

A

Perilymph

Endolymph

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43
Q

Chemically similar to cerebrospinal fluid

Surrounds the membranous labyrinth

A

Perilymph

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44
Q

Within the membranous labyrinth

Has a high level of potassium ions (K+) which plays a role in generation of auditory signals

A

Endolymph

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45
Q

slide 23 image

A

23

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46
Q

is the oval central portion of the bony labyrinth

A

Vestibule

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47
Q

Part of the membranous labyrinth is within the vestibule, and is composed of two sacs,

A

the utricle and saccule, connected by a duct

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48
Q

The vestibule also contains the

A

oval window (vestibular window)

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49
Q

The semicircular canals are three bony structures

At approximately right angles to each other

Named according to position:

A

Anterior (oriented vertically)
Posterior (oriented vertically)
Lateral (oriented horizontally)

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50
Q

Semicircular canals :

A swollen enlargement called the

A

ampulla is at one end of each canal

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51
Q

Semicircular canals :

Parts of the membranous labyrinth that are inside the semicircular canals are called

A

semicircular ducts; they connect to the utricle of the vestibule

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52
Q

they connect to the utricle of the vestibule

A

semicircular ducts

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53
Q

Caused by an increased amount of endolymph, which enlarges the membranous labyrinth

Symptoms include fluctuating hearing loss (due to distortion of the basilar membrane), roaring tinnitus (ringing in the ears), whirling vertigo (dizziness)

The hearing may be lost over a number of years

A

Ménière’s disease

54
Q

The vestibular branch of the vestibulocochlear nerve (cranial nerve VIII) consists of three nerves:

A

utricular, saccular, and ampullary

55
Q

The nerves synapse with receptors for equilibrium

They have both first-order sensory neurons and motor neurons:

A

Sensory neurons carry sensory information from the receptors

Motor neurons carry feedback signals to the receptors to modify their sensitivity

56
Q

Cell bodies of the sensory neurons are located in the

A

vestibular ganglia

57
Q

Cell bodies of the motor neurons are in the pons, and project to the

A

semicircular canals, saccule, and utricle

58
Q

The cochlea is a bony spiral canal

Its central supporting core is called the

A

modiolus

59
Q

The cochlea has a Y-shaped partition that forms three channels:

A

Scala media (AKA cochlear duct) in the forks of the Y

Scala vestibuli, on one side, ending at the oval window

Scala tympani, the other side, ending at the round window

60
Q

The scala vestibuli and scala tympani contain

Scala vestibuli and scala tympani are separated by the stem of the “Y” except at the apex of the cochlea, where there is an opening called the…

A

perilymph

…helicotrema (“the hole in the spiral”) that joins them

61
Q

The ___ opens into the vestibule (hence its name)

A

scala vestibuli

62
Q

The _____ (AKA scala media) is between the wings of the “Y”

A

cochlear duct

63
Q

The scala media is a continuation of the membranous labyrinth into the cochlea

Membranes contain the perilymph within the different scalae:

A

Vestibular membrane of the scala vestibuli

Basilar membrane of the scala tympani

64
Q

The ____ (AKA organ of Corti) is on the basilar membrane, within the cochlear duct

It contains hair cells, which are the receptors for hearing

A

spiral organ

65
Q

It contains hair cells, which are the receptors for hearing

A

spiral organ (AKA organ of Corti)

66
Q

Hair cells of the spiral organ are in two groups:

A

Inner hair cells, arranged in a single row

Outer hair cells, arranged in three rows

67
Q

A hair bundle is at the apical tip of each hair cell

Stereocilia comprise the “hairs” but they are actually…

A

…long microvilli

68
Q

Inner and outer hair cells synapse with both first-order sensory neurons and with motor neurons from the

A

cochlear branch of the vestibulocochlear nerve (cranial nerve VIII)

69
Q

Cell bodies of sensory neurons are in the

A

spiral ganglion of the cochlea

70
Q

The afferent fibers from the cochlea are myelinated dendrites of bipolar cells of the spiral ganglion. These bipolar neurons are the only neurons that have

A

a myelin sheath surrounding the cell body

71
Q

Cell bodies of motor neurons are in the ___, and project to hair cells of the spiral organ

A

pons

72
Q

The __ ___ projects over the hair cells, and is in contact with them

A

tectorial membrane

73
Q

Alternating high and low pressure regions of a medium (generally air)
Frequency = pitch
Amplitude = volume = intensity
Sympathetic vibrations

A

Sound

74
Q

Human hearing

Frequency range

A

Most acute 500 to 5000 Hertz (cps)

Audible range 20 to 20,000 Hz

75
Q

Threshold defined as 0 dB at 1000 Hz, which is the point at which an average young adult can just distinguish sound from silence

Normal conversation is 60 dB
OSHA requires hearing plan when occupational noise levels exceed 90 dB

Rock concert and headphones produce >110 dB

A

Amplitude

76
Q

STEPS IN HEARING

A
  1. Sounds are directed into the external auditory canal by the auricle
  2. Sound waves strike the eardrum, causing it to vibrate in sympathy
  3. The vibrations are transmitted through the auditory ossicles, and somewhat magnified due to the mechanical relationships of the ossicles
  4. The stapes vibrates, transmitting movements to the oval window, amplifying the energy due to differences between surface areas of eardrum and oval window
  5. Oval window moves in and out, setting up fluid pressure waves in the perilymph
  6. Pressure waves are transmitted from scala vestibuli to the scala tympani
  7. Pressure waves deform the walls of the scala vestibuli and scala tympani pushing the vestibular membrane back and forth
    7a. Pressure waves from the scala vestibuli and scala tympani create pressure waves in the endolymph inside the scala media (cochlear duct)
  8. Pressure waves in the endolymph cause the basilar membrane to vibrate, moving the hair cells of the spiral organ against the tectorial membrane
  9. Pressure waves cause vibration of the secondary tympanic membrane in the round window (no physiological consequence—fluid is incompressible)
77
Q

Hair cells transduce mechanical vibrations into electrical signals by means of

A

mechanically gated ion channels

78
Q

of differing heights comprise the hair bundles at the apex of each hair cell

A

Stereocilia

79
Q

The tips of shorter stereocilia are connected by a __ __ __ to its taller stereocilium neighbor

A

tip link protein

80
Q

A mechanically-gated ion channel called a __ ___ is associated with the tip link proteins

A

transduction channel

81
Q

As stereocilia bend in the direction of the taller stereocilium to which they are connected, the tip links tug on

A

the transduction channels and open them

82
Q

Steps in hearing

The open channels allow ___ in the endolymph to enter the cell

A

cations

83
Q

Cations enter and produce a __ __ __, which spreads along the membrane

A

depolarizing receptor potential

84
Q

Bending the stereocilia in the opposite direction closes transduction channels, allows repolarization, and

A

reduces neurotransmitter release from the hair cells

85
Q

Cell bodies of the first-order sensory neurons are in the spiral ganglia, and their axons comprise the

A

cochlear branch of the vestibulocochlear nerve

86
Q

Axons of the cochlear branch synapse with neurons in the cochlear nuclei in the

A

medulla oblongata (on the same side—no decussation up to this point)

87
Q

Some axons from the cochlear nuclei decussate in the medulla and ascend in the lateral lemniscus on the opposite side, where they terminate in the

A

inferior colliculus of the midbrain

88
Q

Other axons from the cochlear nuclei end in the __ ___ __ in the pons on each side. These also ascend in the lateral lemniscus tracts on both sides, and end in the inferior colliculi

A

superior olivary nucleus

89
Q

Slight differences in the timing of nerve impulses arriving from each ear at the superior olivary nuclei enable us to

A

determine the direction of sounds

90
Q

Other axons from the cochlear nuclei end in the superior olivary nucleus in the pons on each side. These also ascend in the __ and end in

A

lateral lemniscus tracts on both sides, and end in the inferior colliculi

91
Q

From each inferior colliculus, nerve impulses are conveyed to the ___________________, then to the primary auditory area of the cerebral cortex

A

medial geniculate nucleus of the thalamus

92
Q

From each inferior colliculus, nerve impulses are conveyed to the medial geniculate nucleus of the thalamus, then to the

A

primary auditory area of the cerebral cortex

93
Q

may be caused by allergy, high or low blood pressure (blood circulation problems), a tumor, diabetes, thyroid problems, injury to the head or neck, as well as a variety of medications including anti-inflammatory medicines, antibiotics, sedatives, antidepressants, and aspirin

A

Tinnitus

94
Q

The exact mechanism that causes tinnitus is not known. Younger people tend to have tinnitus as a result of exposure to loud noise. Older people who experience tinnitus often have a certain amount of hearing impairment related to the natural aging process

A

cool

95
Q

Exceptionally loud noises damage stereocilia, causing them to mistakenly continue sending sound information to the auditory nerve as they move randomly in a state of irritation.

Sometimes tips of some stereocilia break off

Ringing is temporary because the tips grow back within about 24 hours
Unlike many other forms of tinnitus, this form has a known cause

A

Ringing due to loud noises

96
Q

Deafness is significant or total hearing loss

Two broad types:

A

Sensorineural deafness, due to damage or disease of the sensorineural pathway (hair cells, cochlear branch of cranial nerve VIII)

Conduction deafness (conductive deafness), caused by impairment of mechanisms in the external and middle ear (otosclerosis (deposition of new bone around the oval window)), impacted cerumen, eardrum injury, stiffening of the joints of the auditory ossicles

97
Q

due to damage or disease of the sensorineural pathway (hair cells, cochlear branch of cranial nerve VIII)

A

Sensorineural deafness,

98
Q

caused by impairment of mechanisms in the external and middle ear (otosclerosis (deposition of new bone around the oval window)), impacted cerumen, eardrum injury, stiffening of the joints of the auditory ossicles

A

Conduction deafness (conductive deafness),

99
Q

Exposure to loud noises damages hair cells of the cochlea

Continued exposure to high-intensity sounds is a cause of deafness

A

Noise-induced deafness

100
Q

The cochlea has the ability to produce sounds, which are termed

A

otoacoustic emissions

101
Q

They are usually inaudible, but can be picked up by a sensitive microphone next to the eardrum

Cause by vibrations of the outer hair cells in response to signals from motor neurons and to sound waves

A

otoacoustic emissions

102
Q

Otoacoustic emissions

The vibrations of the outer hair cells set up a traveling wave that goes back toward the ____, causing the eardrum to vibrate

A

stapes

103
Q

This provides a fast, inexpensive, noninvasive way to screen newborns for hearing defects, since in deaf babies ______ are not produced, or are greatly reduced in size

A

otoacoustic emissions

104
Q

Equilibrium

Two types of equilibrium (balance) exist

A

Static equilibrium—the maintenance of the position of the body (mainly the head) relative to the force of gravity

Dynamic equilibrium—maintenance of body position (mainly the head) in response to sudden movements

105
Q

the maintenance of the position of the body (mainly the head) relative to the force of gravity

A

Static equilibrium—

106
Q

maintenance of body position (mainly the head) in response to sudden movements

A

Dynamic equilibrium—

107
Q

Dynamic equilibrium

_____ is a complex of strange eye movements that occurs during and immediately after rotational movement

Nystagmus can be accompanied by vertigo

A

Vestibular nystagmus

108
Q

Equilibrium pathway

Cell bodies of the first-order sensory neurons are in the __ __, and their axons comprise the…

A

vestibular ganglia

…and their axons comprise the vestibular branch of the vestibulocochlear nerve

109
Q

Equilibrium pathway

Most of the axons of the vestibular branch synapse with neurons in the vestibular nuclei in the….

A

…medulla oblongata (on the same side—no decussation up to this point)

110
Q

Equilibrium pathway

Most of the axons of the vestibular branch synapse with neurons in the vestibular nuclei in the….

A

…medulla oblongata (on the same side—no decussation up to this point)

111
Q

Equilibrium pathway

The remaining axons enter the cerebellum through the….

The ___ and ____ are connected by bidirectional pathways

A

….inferior cerebellar peduncles.

The cerebellum and vestibular nuclei are connected by bidirectional pathways

112
Q

Equilibrium pathway

The remaining axons enter the cerebellum through the….

The ___ and ____ are connected by bidirectional pathways

A

….inferior cerebellar peduncles.

The cerebellum and vestibular nuclei are connected by bidirectional pathways

113
Q

Equilibrium pathway

The vestibular nuclei integrate information from…

A

vestibular, visual, and somatic receptors, then send commands via a number of nuclei and tracts:

114
Q

Equilibrium pathway

The vestibular nuclei integrate information from…

A

vestibular, visual, and somatic receptors, then send commands via a number of nuclei and tracts:

115
Q

Motion sickness

Appears to be due to sensory input mismatch:

Within a moving vehicle the immediate frame of reference (the vehicle) is

A

stationary according to visual inputs

116
Q

Motion sickness

Appears to be due to sensory input mismatch:

A discrepancy arises when . . .

A

The surroundings are moving according to visual input

The vehicle is moving according to vestibular inputs (acceleration, deceleration, tilting, etc.)

117
Q

Motion sickness

Appears to be due to sensory input mismatch:

The brain receives conflicting information, and its “confusion” causes

A

motion sickness

118
Q

The receptor organs for equilibrium are called the vestibular apparatus, and include

A

Saccule
Utricle
Semicircular ducts (within the semicircular canals)

119
Q

Walls of the utricle and saccule contain a small region called a ___?

___ it’s horizontal in utricle

vertical in the saccule

A

macula
Macula is horizontal in the utricle
Macula is nearly vertical in the saccule

120
Q

The maculae consist of two kinds of cells:

A

Hair cells, which are sensory receptors

Supporting cells, which produce a gelatinous glycoprotein layer called the otolithic membrane, that rests on the hair cells

121
Q

Hair cells are composed of hair bundles, having two types of hairs

A

Stereocilia (actually microvilli)

Kinocilium
One kinocilium per bundle
A true cilium
Longer than the longest stereocilia of the bundle

122
Q

The stereocilia are connected by

A

tip links (same as in the cochlea)

123
Q

A layer of calcium carbonate crystals, called ___, extends over the surface of the otolithic membrane

A

otoliths

124
Q

Physiology of static equilibrium

When the head is tilted or accelerates, inertia causes the otolithic membrane to

A

slide over the hair cells, bending the hair bundles

125
Q

Physiology of static equilibrium

Bending the hair bundles in one direction stretches the tip links, opening the mechanically-gated transduction channels, and producing

A

depolarizing receptor potentials and release of neurotransmitter

126
Q

Physiology of static equilibrium

Bending the hair bundles in the other direction closes the __ and produces what?

A

transduction channels and produces repolarization

127
Q

Physiology of static equilibrium

The maculae respond only to changes in ?

They adapt ___ ?

They do not report on unchanging head positions

A

The maculae respond only to changes in acceleration or velocity of head movement

They adapt quickly

They do not report on unchanging head positions

128
Q

Dynamic equilibrium

The three semicircular ducts plus the saccule and utricle function in dynamic equilibrium (there are also visual and proprioceptor inputs, but these are not located in the

A

inner ear, so they are not generally discussed)

129
Q

Dynamic equilibrium

Within the ampulla (dilated portion) of each duct is a small elevation called a crista (crista ampullaris)
Each crista contains

A

Hair cells
Supporting cells
Cupula, a mass of gelatinous material

130
Q

Dynamic equilibrium

When the head moves the endolymph within the ampulla lags behind due to ___

This causes?

A

inertia

This causes the hair cells to bend, producing receptor potentials

131
Q

Dynamic equilibrium

Receptor potentials lead to nerve impulses that pass along the

A

vestibular branch of the vestibulocochlear nerve (cranial nerve VIII)

132
Q

Dynamic equilibrium

If the body continues to rotate at a constant rate, the endolymph eventually __ causing what?

If the body stops suddenly….

A

catches up, and stimulation of the hair cells ends

If the body stops suddenly, the endolymph keeps moving

A&P I (21 decks)

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