The Ear and Facial Nerve Flashcards Preview

Structure and Function Test 1 > The Ear and Facial Nerve > Flashcards

Flashcards in The Ear and Facial Nerve Deck (97)
Loading flashcards...
1
Q

Located within the pertrous portion of the temporal bone

A

The auditory and vestibular apparatus and the majority of the course of the facial nerve (CN VII)

2
Q

The ear is divided into what three portions?

A

External, middle, and inner

3
Q

Serves as the collector and conductor of sound waves

A

External ear

4
Q

The external ear is composed of the

A

Pinna and External ear canal

5
Q

The external ear canal is derived from the

-Lined by ectoderm epithelium

A

First pharyngeal cleft

6
Q

The outer portion of the external ear is cartilaginous and the inner portion is

A

Bony

7
Q

Modified sweat glands in the skin of the external ear

A

Ceruminous glands

8
Q

Secrete cerumen (ear wax) which functions to keep the canal moist and to protect it from bacteria and infection

A

Ceruminous glands

9
Q

Derived from 6 swellings (hillocks) on the first and second pharyngeal arches that border the pharyngeal cleft

A

Auricle

10
Q

The canal leads to the

A

Tympanic membrane

11
Q

The tympanic membrane is derived from fusion of the

A

Ectoderm of first pharyngeal cleft and endoderm of first pharyngeal pouch

12
Q

Separates the external ear from the middle ear

A

Tympanic membrane

13
Q

The external ear receives MOST of its innervation from

A

CN V3

-also receives innervation from branches of CN VII, IX, and X

14
Q

Air filled cavity containing structures that allow it to serve as a conductor and amplifier of sound vibrations

A

Middle Ear (Tympanic cavity)

15
Q

What are the three ossicles within the middle ear?

A

Malleus, inus, and stapes

16
Q

Attached to the inner surface of the tympanic membrane

A

Malleus

17
Q

There are synovial joint connecting

A

Malleus to incus and incus to stapes

18
Q

The footplate of the stapes lies within the

A

Oval window of the inner ear

19
Q

The impingment of sound waveson the tympanic membrane causes the membrane to

A

Vibrte

20
Q

This in turn causes the ossicles to vibrate, which transmits the vibration to the

A

Inner ear

21
Q

The combination of the ratio of size of tympanic membrane to the size of the stapes footplate, and the shape and orientation of the ossicles result in amplification of approximately

A

30 dB

22
Q

this compensates for the loss of energy at the

A

Air/water interface of the inner ear

23
Q

The sensory receptors of the organ of Corti in the cochlea are in an

A

Aqueous environment

24
Q

What are the two muscles in the inner ear?

-reduce the amplitude of vibration that reaches the inner ear

A

Tensor tympani and stapedius

25
Q

The tensor tympani and stapedius reduce the amplitude of vibration that reaches the inner ear, which protects the

A

Cochlear hair cells

26
Q

A lesion of the facial nerve (VII) may cause

A

Hyperacusis

27
Q

And increased perception of loudness because of the loss of action of the stapedius

A

Hyperacusis

28
Q

The middle ear is connected to the nasopharynx by the

A

Auditory (Eustachian) tube

29
Q

Allows for equalization of air pressure between the middle ear and the environment

-provides the pathway for spread ofinfection from the pharynx to the middle ear

A

Auditory (Eustachian) tube

30
Q

The middle ear cavity is also continuous with the

A

Mastoid air cells

31
Q

A middle ear infection can spread to the

A

Pharnx or mastoid air cells

32
Q

The middle ear, auditory tube, and mastoid air cells are all derived from the

A

First pharyngeal pouch (lined by endodermal epithelium)

33
Q

The malleus, incus (neural crest) and tensor tympani (mesoderm) are derived from the

A

First pharyngeal arch

34
Q

The stapes (neural crest) and stapedius (mesoderm) are derived from the

A

Second pharyngeal arch

35
Q

The tensor tympani is innervated by

A

CN V3 (nerve of the first arch)

36
Q

The stapedius is innervated by

A

CN VII (nerve of the second arch)

37
Q

The mucosa of the middle ear cavity is innervated by

-also innervates mucosa of pharynx

A

CN IX (tympanic branch)

38
Q

Contains the organ for audition, the cochlea, and the organs for vestibular sensation

A

Inner ear

39
Q

What are the organs for vestibular sensation?

A

3 semicircle canls, utricle, and saccule

40
Q

Detect rotational movements of the head

-in the three planes of space and each is perpendicular to the other two

A

The 3 semicircle canals

41
Q

Detect translational movements of the head

A

Utricle and saccule

42
Q

Detects linear motion in a horizontal plane

A

Utricle

43
Q

Detects linear motion in a verticle plane

A

Saccule

44
Q

Within the cochlea is the cochlear duct, which contains the

A

Organ of Corti

45
Q

On the organ of corti is where we find the

A

Cochlear hair cells

46
Q

With agin, there is often a loss of hair cells beginning at the high frequency end of the cochlea, resulting in

A

Hearing loss (presbycusis)

47
Q

The cochlear duct is filled with

A

Endolymph

48
Q

The cochlear duct is surrounded by

A

Perilymph

49
Q

In contact with the footplate of the stapes at the oval window

A

Perilymph

50
Q

Vibration at the footplate of the stapes causes a vibratory wave through the perilymph, which in turn causes vibration of the

A

Organ of Corti

51
Q

This vibration is transduced by the hair cells to a neural impulse which is carried by the

A

Cochlear division of CN VIII

52
Q

Innervates the hair cells

A

Cochlear division of CN VIII

53
Q

Within the semicircular canals, the utricle and saccule are the maculae, which contains the

A

Vestibular hair cells

54
Q

The maculae also contians

A

Endolymph

55
Q

Movement of the head causes displacement of these hair cells, and this displacement is transduced into nerve impulses which are carried in the

A

Vestibular division of CN VIII (innervates the hair cells)

56
Q

The inner ear is derived from a thickening of the skin ectoderm called the

A

Otic placode

57
Q

Hearing losses may be categorized as

A

Conductive hearing loss or sensorineural hearing loss

58
Q

If there is a defect in the external or middle ear that prevents or diminishes the conduction of vibration to the inner ear, it is a

A

Conductive hearing loss

59
Q

A ruptured tympanic membrane, otosclerosis, dislocation of ossicular joints, or excessive cerumen in external ear canal are all examples of

A

Conductive hearing loss

60
Q

If there is a defect in the inner ear or neural pathway or neural pathway from the inner ear to the auditory cortex of the brain, we have a

A

Sensorineural hearing loss

61
Q

Damage to cochlear hear cells from overstimulation, aging or infection, or a lesion of CN VIII or the auditory pathways of the brain are examples of

A

Sensorineural hearing loss

62
Q

What is one way we test for sensorineural and conductive hearing loss?

A

Weber test

-tuning fork placed against the bone of the skull at the mid line. If sound is heard equally on both sides than things are normal

63
Q

If there is a sensorineural hearing loss on one side, then with the Weber test, the patient will perceive the sound as coming from the

A

Contralateral side (the normal side)

64
Q

The Weber test allows the clinician to bypass the conductive portion of the ear (external and middle ear) by having the vibration reach the inner ear bone by

A

Conduction

65
Q

With a Weber test. if there is a CONDUCTIVE hearing loss, what will we see?

A

Patient will perceive sound as coming from the side with the hearing loss

66
Q

Ambiguous with regard to which type of hearing loss exists on which side

A

Weber test

67
Q

A vibrating tuning fork is initially placed on the patient’s mastoid process. The vibration is conducted to the patient’s inner ear by bone conduction

A

RInne test

68
Q

In the Rinne test, as the amplitude of the vibration decreases, the sound perceived by the patient decreases in volume. The patient is asked to tell the examiner when the sound can no longer be heard. At that point, the examiner moves the vibrating tuning fork to the outside of the

A

External ear canal

69
Q

If the patient reports that they can hear the sound again then they are normal, but if they can not hear the sound outside of the external ear, then they have a

A

Conductive hearing loss

70
Q

The Rinne test will detect

A

CONDUCTIVE hearing loss

71
Q

The facial nerve enters the temporal bone through the

A

Internal auditory meatus

72
Q

The facial nerve then passes across the top of the inner ear to reach the

A

Geniculate ganglion

73
Q

In the geniculate ganglion are found the cell bodies of the

A

General sensory and special sensory neurons of the facial nerve

74
Q

Because the geniculate ganglion is a sensory ganglion, it contains only sensory cell bodies and there are

A

No synapses in this ganglion

75
Q

Pass through the geniculate ganglion

A

Motor fibers (somatic and preganglionic parasympathetic) of facial nerve

76
Q

At the geniculate ganglion, the facial canal, which contains the facial nerve turns posteriorly (the genu) and then continues along the

A

Wall of the middle ear

77
Q

At the genu, the facial nerve gives rise to the

A

Greater petrosal nerve

78
Q

The greater petrosal nerve contains preganglionic parasympathetic fibers destined for the

A

Pterygopalatine ganglion

79
Q

Also contains special sensory taste fibers destined for the palate

A

Greater petrosal nerve

80
Q

As the facial nerve continues through the facial canal, it gives rise to the branches to the

A

Stapediues (somatic motor) and also the chorda tympani

81
Q

Contains special sensory taste fibers coming from the anterior 2/3 of the tongue

A

Chorda tympani

82
Q

The chorda tympani also contains preganglionic parasympathetic fibers destined for the

A

Submandibular ganglion (via the lingual nerve)

83
Q

The chorda tympani leaves the facial canal and passes through the middle ear cavity, passing BETWEEN the

A

Malleus and incus (to reach the petrotympanic fissure)

84
Q

Does NOT innervate anything in the middle ear

A

Chorda tympani

85
Q

After exiting through the petrotympanic fissure, the chorda tympani enters the infratemporal fossa and joins the

A

Lingual nerve (branch of CN V3)

86
Q

Serves as the pathway to carry the sensory taste fibers to the anterior 2/3 of the tongue and to carry preganglionic parasympathetic fibers to the floos of the mouth where the submandibular ganglion is located

A

Lingual nerve

87
Q

The preganglionic parasympathetic fibers from the lingual nerve are headed to the

A

Submandibular ganglion

88
Q

The facial nerve leaves the temporal bone by exiting through the

A

Stylomastoid foramen (in the mandibular fossa)

89
Q

After leaving through the stylomastoid foramen, the facial nerve gives off the

A

Posterior auricular branch

90
Q

Provides sensory innervation behind the ear and somatic motor innervation to some skeletal muscle of the posterior portion of the scalp

A

Posterior auricular branch of facial nerve

91
Q

The facial nerve then passes through the parotid bed to reach and innervate the

A

Muscles of facial expression, the posterior belly of the digastric and the stylohyoid muscles

92
Q

Weakness or paralysis of facial muscles, loss of taste or sensation of the anterior 2/3 of the tongue, and decreased salivation are all symptoms of a

A

Facial nerve lesion

93
Q

A major sign of a facial nerve lesion proximal to the geniculate ganglion is

A

Reduced lacrimation

94
Q

A major sign of a facial nerve lesion between the geniculate ganglion and stapedius is

A

Hyperacusis

95
Q

We would not expect lacrimation or hyperacusis, but we would expect all other symptoms with a lesion of the facial nerve between

A

Stapedius and chorda tympani

96
Q

A lesion of the facial nerve between the chorda tympani and stylomastoid foramen would present with

A

Los of facial muscle function and sensory abnormality behind the ear

97
Q

A lesion of the facial nerve within the parotid gland would only present with

A

Loss of facial muscle function

Decks in Structure and Function Test 1 Class (61):