exam 4: CN VIII (36) Flashcards

1
Q

The ear allows for the transformation of sound pressure waves into

A

electrical energy

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2
Q

The external ear captures sound (longitudinal) waves and transmits this energy to the middle ear via the ___________

A

tympanic membrane

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3
Q

The_____________ of the middle ear convert these pressure waves into mechanical energy.

A

ossicles (small bones)

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4
Q

Vibrations at the oval window by the stapes produces pressure waves within the _____________

A

perilymph (fluid) of the inner ear.

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5
Q

Movement of the perilymph displaces the membranes (tectorial, basement) affiliated with the cochlear duct, activating _______________

A

mechanically-gated ion channels of receptor (hair) cells.

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6
Q

___________ release neurotransmitter onto dendrites of cochlear neurons, transducing
the stimulus into an electrical impulse within cochlear neurons.

A

Hair cells

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7
Q

Movements of the head in various orientations activates ____________

A

mechanically-gated ion channels of receptor (hair) cells

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8
Q

Release of neurotransmitter by hair cells stimulates firing of electrical impulses by

A

vestibular neurons

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9
Q

Rotational movements of the head results in movement of fluids (perilymph, endolymph) within ______________stimulating hair cells affiliated with specialized organs _________

A

semicircular canals and ducts
crista ampullaris within the ducts

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10
Q

Translational movements of the head are detected by specialized organs _____________ that contain _______________________

A

macula utriculi, macula sacculi) that contain otoliths (ear stones)

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11
Q

External (outer) ear parts

A

▪ Pinna (a.k.a., auricle)
▪ Ear canal

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12
Q

Main divisions of the ear

A

1) External (outer) ear
2) Middle ear
3) Inner ear

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13
Q

what are the parts of the ear canal

A

▪ Vertical part
▪ Horizontal part– External acoustic meatus

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14
Q

Middle ear is housed in _____________

A

tympanic part of temporal bone

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15
Q

Parts of the Middle ear (3)

A

▪ Tympanic membrane (ear drum)
▪ Tympanic bulla (tympanic cavity)
▪ Auditory ossicles with associated muscles and
ligaments

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16
Q

Middle ear communicates with the _____________

A

nasopharynx via the auditory
tube

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17
Q

Inner ear housed in what part of the skull

A

petrous part of temporal bone

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18
Q

parts of the Inner ear

A

▪ Osseous labyrinth
▪ Membranous labyrinth

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19
Q

Auditory tube opens rostrally into the

A

nasopharynx = pharyngeal opening of the auditory tube

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20
Q

importance of the Auditory tube

A

Equalization of pressure; drainage of middle ear fluids

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21
Q

importance of the Tympanic bulla

A

▪ Hypo-expansion of middle ear cavity
▪ Divided in the cat

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22
Q

Bony promontory is a ventral expansion of the

A

petrous temporal bone

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23
Q

Tympanic plexus lies over its surface

A

Bony promontory

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24
Q

Ossicles (3 parts)

A

malleus, incus, stapes

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25
Q

middle ear components

A

▪ Auditory tube
▪ Tympanic bulla
▪ Bony promontory
▪ Ossicles (malleus, incus, stapes)

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26
Q

Passageway of communication between nasopharynx (external environment) and middle ear cavity.

A

auditory tube

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27
Q

primary function of auditory tube

A

equalize air pressure between middle ear and atmosphere

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28
Q

T/F auditory tube is normally open

A

false; Normally closed, opens when muscles connected to it contract

▪ Major contributor: tensor veli palatini muscle

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29
Q

auditory tube is important for drainage of

A

Drainage outlet for middle ear fluids

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30
Q

Clinical Connections of auditory tube:

Obstructions of auditory tube causes _________

A

increased pressure in middle ear cavity. Painful!

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31
Q

Clinical Connections of auditory tube:
Middle ear infections (otitis media) can cause swelling and blockage of _________

A

blockage of auditory tube with resultant effusion

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32
Q

Auditory tube:

T/F Polyps (middle ear, nasopharyngeal) are more likely to develop in cats

A

true

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33
Q

can there be obstruction of auditory tube.

A

YES

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34
Q

The tympanic bulla is divided into 2 compartments in the cat:

list them

A

▪ Ventromedial (larger compartment)
▪ Dorsolateral (smaller compartment)

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35
Q

identify the white and clear arrow

A
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36
Q

T/F bony promontory is affiliated with lots of nerves

A

true

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37
Q

Aggressive surgical curettage, middle ear polyps, and middle ear effusion can affect the nerves coursing through the _________

A

middle ear

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38
Q

Horner syndrome

what axons are associated

A

Sympathetic post-ganglionic axons

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39
Q

Chorda tympani nerve of CN VII:

hypogeusia/ageusia =

A

decreased/loss of taste

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40
Q

Tympanic plexus of CN IX:

hypogeusia/ageusia; decreased production of ______________

A

saliva via parotid salivary gland

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41
Q

the “handle” of the “hammer” is
embedded in the tympanic membrane

what is the handle and hammer referring to

A

The manubrium (“handle”) of the malleus (“hammer”)

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42
Q

Vibrations of the tympanic membrane, due to sound pressure waves, move the __________

A

malleus

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43
Q

The tympanic membrane has inner and
outer laminae and the__________ is
embedded between these.

A

manubrium

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44
Q

Middle ear ossicles:

Contraction of the_________________
dampens the movement of the malleus.

A

tensor tympani muscle

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45
Q

what is muscle is being pointed to

A

tensor tympani muscle

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46
Q

identify

A

the tympanic bulla

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47
Q

what kind of joints connect the middle ear
ossicles

A

Diarthrotic (synovial) joints

48
Q

Movement of the malleus will, in turn, result in the movement of the ___ and ___

A

incus and stapes

49
Q

Contraction of the _________ dampens the movement of the stapes at the oval window

A

stapedial muscle

50
Q

▪ Arthritis – __________ hearing impairment

A

conductive

51
Q

weakened or loss of middle ear reflexes

A

Myasthenia gravis

52
Q

Caverns and tunnels within petrous temporal bone.

A

Osseous Labyrinth

53
Q

Osseous Labyrinth and Membranous Labyrinth make up the _______

A

inner ear

54
Q

Epithelial membrane sac within the osseous labyrinth.

A

Membranous Labyrinth

55
Q

Regions of the osseous labyrinth include( 3)

A

▪ Vestibule (with vestibular, or oval, window)
▪ Cochlea (with cochlear, or round, window)
▪ Semicircular canals with ampullae

56
Q

osseous labryinth contain (perilymph/endolymph)

A

▪ Contains perilymph

57
Q

perilymph is similar to what kind of fluid

A

▪ Similar to CSF and extracellular fluid
▪ Low in K+ (~7 mM); high in Na+ (~140 mM)

58
Q

The receptor organs of the inner ear are
components of the______________

A

membranous labyrinth

59
Q

what is the Organ of hearing

A

Cochlear duct

60
Q

what are the vestibular organs

A

▪ Ampullae of semicircular ducts
▪ Utriculus
▪ Saccule

61
Q

membranous labyrinth contains (endolymph/ perilymph)

A

endolymph

62
Q

endolymph is similar to what fluid

A

▪ Similar to intracellular fluid
▪ High in K+ (~150 mM); low in Na+ (~1 mM

63
Q

Excavated space within the petrous temporal
bone

A

osseous cochlea

64
Q

_____________ is centrally located within the space(osseous cochlea)

A

The bony modiolus (shaped kind of like a
screw)

65
Q

The organ of hearing (a.k.a., organ of Corti) is a component of the ______________

A

membranous labyrinth.

66
Q

Membranous cochlea:
▪ Extends from the “shelves” of the _____________

A

modiolus

67
Q

Membranous cochlea:
▪ Contains specialized sensory cells (hair cells) that are ____________ activated

A

mechanically (mechanoreceptors)

68
Q

Membranous cochlea:
mechanoreceptors release neurotransmitter onto what kind of neurons

A

bipolar (SSA) neurons

69
Q

hair transduction:

Cell bodies of cochlear SSA neurons
are grouped within_____________

A

spiral ganglia

70
Q

spiral ganglia (sensory/motor)

A

sensory

71
Q

Axons from the spiral ganglia pass
through the ___________and extend to the ____________where they synapse in cochlear nuclei.

A

internal acoustic meatus and extend to the brainstem (myelencephalon)

72
Q

identify

A

spiral ganglia

73
Q

Vestibular transduction:

Hair cells are located in specialized organs of the semicircular ducts (cristae ampullares) and ___________________________

A

vestibule
(macula utriculi, macula sacculi)

74
Q

Vestibular transduction:

Afferent neurons from these sensory organs form the vestibular portion of CN _____

A

CN VIII

75
Q

Vestibular transduction:
Cell bodies of these vestibular SSA neurons are located in the _____________

A

Vestibular ganglia

76
Q

Vestibular transduction:

Axons from the vestibular ganglia pass through the internal acoustic meatus and synapse in the vestibular nuclei of the ________

A

medulla oblongata (myelencephalon)

77
Q

comprised of sensory neuron fibers from
vestibular organs (maculae; cristae ampullares); neuron cell bodies are in vestibular ganglia

A

Vestibular n.

78
Q

comprised of sensory fibers from the organ of Corti; neuron cell bodies are in spiral ganglia

A

Cochlear n.

79
Q

Vestibulocochlear nerve (CN VIII) leaves the petrous temporal bone via the ____________

A

internal acoustic meatus

80
Q

sensory innervation of the ear (4)

A

▪ Cochlear n. of CN VIII
▪ Vestibular n. of CN VIII
▪ Facial n.
▪ Mandibular nerve of CN V

81
Q

Cochlear n. of CN VIII function

A

▪ Hearing (SSA)

82
Q

Vestibular n. of CN VIII function

A

▪ Balance (SSA)

83
Q

Facial n. function for the ear

A

Concave aspect of pinna; large portion
of ear canal (GSA)

84
Q

Mandibular nerve of CN V functions

A

Base of ear; small portion of ear canal
(GSA

85
Q

Motor Innervation of the ear

A

▪ Facial n. (GSE to auricular mm.)

86
Q

what would lesions of CN VII look like (6)

A

▪ Hearing loss

▪ Disorientation

▪ Nausea, loss of appetite

▪ Vestibular ataxia

▪ Head tilt, head turn, circling and/or leaning
towards the side of the lesion

▪ Resting nystagmus (involuntary eye movements); horizontal fast phase away from the side of the lesion

87
Q

The external ear is supported by
the ___________ cartilage

A

auricular

88
Q

what is the proximal and distal end of the auricular cartilage

A

▪ Proximal end of this cartilage =
vertical and horizontal ear canals

▪ Distal end of this cartilage = pinna

89
Q

The shape of the pinna is dependent upon

A

composition of the fibroelastic auricular cartilage

90
Q

T/F The collagen/elastin composition varies among species and breeds

A

true

91
Q

The size and shape of the pinna determines which ____________ optimally and may also
help with ___________

A

sound frequencies are collected
noise reduction

92
Q

what kind of ear is this

A

Non-erect
(Lop-eared)

93
Q

what kind of ear is this

A

Erect
(V-shaped)

94
Q

what kind of ear is this

A

Semi-erect
(Cocked)

95
Q

the auricle( convex and concave) is covered by __________ which extends into the ear canal

A

hairy skin with glands (modified sweat glands) that produce cerumen is found within the ear canal

96
Q

most common tumor of ear is known as

A

Ceruminous gland adenomas

97
Q

Dermatologic disease can lead to ______ in the ear canal

A

otitis externa

98
Q

the visible portion of the external ear has several regions that provide important surgical landmarks

list some

A

▪ Helix
▪ Scapha
▪ Anthelix
▪ Tragus
▪ Antitragus
▪ Tragohelicine incisure
▪ Intertragic incisure
▪ Cutaneous marginal pouch

99
Q

from top to bottom

A

apex
Cutaneous marginal pouch

100
Q

in addition to the auricular cartilage, what are the other 2 cartilages affiliated with the ear

A

annular and scutiform cartilage

101
Q
A
102
Q

the annular cartilage connects the cartilaginous meatus of the horizontal canal with the

A

bony external acoustic meatus

103
Q

the _____________ serves as an attachment site for auricular muscle

A

scutiform cartilage

104
Q

scutiform cartilage: what is its shape

A

A flat, boot-shaped cartilage

105
Q

scutiform cartilage:

where is it located

A

Located medial and rostral to the base of
the auricle

106
Q

scutiform cartilage:

what does it aid in

A

Aids in the redirection of the pull of some
of the auricular muscles.

107
Q

the extensive movement of the auricle is permitted by the attachment of a ____________

A

complex group of auricular muscles
▪ Rostral Auricular Group
▪ Caudal Auricular Group

108
Q

Motor innervation to the external ear is by CN ___

sensory innervation is by CN __,__,__

A

Motor: CN VII
Sensory: CN V, VII, II

109
Q

what nerve is motor to external ear

A

Motor (CN VII)
▪ Auriculopalpebral n.
▪ Rostral auricular n.
▪ Caudal auricular n

110
Q

what nerves are sensory to the external ear

A

Sensory (CN VII):
▪ Internal auricular n. (middle, caudal,
lateral brr.)

Sensory (CN V):
▪ Auriculotemporal n.
▪ Rostral auricular br. (there is a minimal
contribution of fibers from the vagus n. to
this branch)

111
Q

zones of cutaneous innervation of the ear

A
112
Q

nerves of the cervical plexus also supply ___________innervation to the external ear

A

cutaneous (sensory) innervation

▪ Great auricular n.
Ventral branch of C2
▪ Greater (a.k.a., major) occipital n.
Dorsal branch of C2

113
Q

The second cervical nerve (C2) supplies
sensory innervation to the ________ surface of the external ear

A

convex

114
Q

whereas the facial nerve supplies sensory innervation to the_______surface of
the external ear.

A

concave

115
Q

auricular sensory zones of CN II

A

 Great auricular n.
Ventral branch of C2
 Greater (a.k.a., major) occipital n.
Dorsal branch of C2