Exam 4 Ear Flashcards
1
Q
What is the ectodermal thickening on the lateral “head”
A
Placode
2
Q
What does the placode give rise to
A
The auditory pit, then auditory vesicle
3
Q
What does the auditory vesicle give rise to
A
Most of the membranous inner ear
4
Q
What secondary embryologic feature is derived from the 1st pharyngeal pouch
A
The auditory tube and tympanic cavity
5
Q
What is the malleus derived from
A
The dorsal end of the ventral mandibular cartilage
6
Q
What is the incus developed from
A
The dorsal end of the first pharyngeal arch
7
Q
What is the stapes derived from
A
The dorsal end of the second pharyngeal arch
8
Q
What is the tympanic membrane developed from
A
Interstitial mesoderm
9
Q
What is the external acoustic canal developed from
A
First pharyngeal groove
10
Q
What is the auricle developed from
A
A groove next to the 1st pharyngeal groove
11
Q
What are the 3 portions of the ear
A
External, middle, inner
12
Q
What are the 2 features of the external ear
A
The auricle and external acoustic meatus
13
Q
What is another name for the auricle of the external ear
A
Pinna
14
Q
What is the function of the auricle
A
Funnel sound waves into external acoustic meatus
15
Q
What are the 3 extrinsic muscles of the auricle
A
Anterior auricular muscle, superior auricular muscle, and posterior auricular muscle
16
Q
What are the intrisic muscles of the auricle
A
Helicus major/minor, tragicus, antitragicus, transverse muscle of the auricle, oblique muscle of the auricle
17
Q
What is the shape of the external acoustic meatus
A
S shaped
18
Q
Where is the medial 2/3 of the external acoustic meatus
A
Within temporal bone
19
Q
What glands are located in the external acoustic meatus
A
Modified sweat glands producing cerumen
20
Q
Where does the external acoustic meatus terminate
A
At the tympanic membrane
21
Q
How is blood supplied to the external ear
A
Posterior auricular branch, anterior auricular branch, auricular branch
22
Q
What is the sensory supply to the external ear
A
Auriculotemporal nerve, auricular branch, great auricular nerve (C2 and C3)
23
Q
What is the motor supply of the external ear
A
Temporal and posterior auricular branches
24
Q
What is the sympathetic supply to the external ear
A
From superior cervical ganglion
25
Where is the middle ear
Small space between tympanic membrane and inner ear
26
What are the 2 parts of the middle ear
Tympanic cavity and epitympanic recess
27
What are the 3 small bones in the middle ear
Incus, malleus, stapes
28
What 2 muscles are located in the tympanic cavity
Stapedius and tensor tympani
29
What is the blood supply to the middle ear
Anterior tympanic branch and tympanic branch
30
What is the sensory supply of the middle ear
Tympanic nerve of CN IX (pregang parasymp)
31
What is the motor supply of the middle ear
Nerve to stapedius (CN VII) supplying stapedius, medial pterygoid nerve
32
What does the medial pterygoid nerve of mandibular division supply within the middle ear
Tympani muscle
33
What is the sympathetic supply of the middle ear
Carotympanic nerves carry vasomotor and secretomotor fibers from superior cervical ganglion by way of internal carotid plexus
34
What is another name for the inner ear
Labyrinth
35
What are the two parts to the labyrinth
Bony and membranous
36
What is the bony labyrinth an enclosure for
The membranous labryinth
37
What is the membranous labyrinth surrounded by
Surrounded by perilymph within the bony labyrinth
38
What are the 3 parts of the bony labyrinth
The cochlea, the vestibule, the semicircular canals
39
What is contained within the cochlea
The cochlear duct
40
Where is the utricle and saccule contained
The vestibule
41
What contains the semicircular ducts
The anterior/superior,lateral, posterior semicircular canals
42
What connects the utricle and saccule
Utricosaccular duct
43
Where is the endolymphatic duct located
From utricosaccular duct to just below the dura ending at the endolymphatic sac
44
What is a reservoir for endolymph
The endolymphatic sac
45
What connects the saccule with cochlear duct
The ductus reuniens
46
the bony part of the cochlear that consists of a tube coiled around a cone shaped central bony structure called what
The modiolus
47
How many times does the cochlea wrap around the modiolus
2.5-2.75 times
48
What is the apex of the cochlea
The cochlear capula directed anterolaterally
49
What is the bony ridge that connects the cochlea to the modiolus
The lamina of the modiolus
50
What are the 3 channels of the cochlea
Cochlear duct, scala vestibuli, and scala tympani
51
Where does the cochlear duct end
At the apex of the cochlea
52
The scala vestibuli and scala tympani communicate with each other at the apex through a channel called what
The helicotrema
53
Is the scala vestibuli filled with endolymph or perilymph
Filled with perilymph
54
What forms the base of the scala vestibuli and what is its purpose
The oval window forms the base so vibrations are transmitted into the scala vestibuli as the stapes vibrates
55
Where is the scala vestibuli located and where is the scala tympani located
Scala vestibuli = above cochlear duct, scala tympani = below the cochlear duct
56
Vibrations transmitted through the scala vestibuli pass to the scala tympani via what
The helicotrema
57
What is the base of the scala tympani
The round window
58
How is the cochlear duct anchored to the outer wall of the cochlea
By the spiral ligament
59
What separates the cochlear duct from the scala vestibuli
The vestibular membrane
60
What separates the scala tympani from the cochlear duct
The basilar/spiral membrane
61
Where is the spiral organ located
On the floor of the cochlear duct, attached to the basilar/spiral membrane
62
What part of the inner ear is sensitive to frequency and amplitude of sound waves that enter the cochlea
The spiral organ
63
What are the hair cells of the spiral organ covered by
The tectorial membrane
64
What information is conveyed by spiral organs
It is conveyed from receptor cells to primary sensory neurons, cells bodies for the neurons are in the spiral ganglion
65
After sound waves enter the external acoustic meatus what is impacted
The tympanic membrane vibrates
66
How does sound travel through the ossicles of the middle ear (i.e. the order of them)
Malleus, incus, stapes transmit the vibrations
67
How much is sound amplified by going through the ossicles of the middle ear
Amplifies the vibration 1.2 times
68
What does the foot of the stapes articulate with
The oval window forming the base of the scala vestibuli
69
Since the oval window is smaller than the tympanic membrane how much are the vibrations amplified
Another 17 times
70
After vibrations travel through the oval window where do they go
Transmitted through perilymph of scala vestibuli and scala tympani to the round window
71
What does the wave through the perilymph of the scala vestibuli/tympani through the round window then travels through perilymph causing what to vibrate
The basilar membrane
72
What does the vibration of the basilar membrane stimulate
Receptors in the spiral organ
73
After vibrations stimulate the receptors in the spiral organ where do they then go
The cochlear nerve
74
What are the two sacs of the vestibular labyrinth
The saccule and utricle along with 3 semicircular ducts
75
What fluid is contained within the structures of the vestibular labyrinth
Endolymph
76
What does the saccule of the vestibular labyrinth communicate with
The cochlear duct via the ductus reuniens
77
Which is larger the utricle or saccule and what does it communicate with
The utricle is larger and communicates with all 3 semicircular ducts
78
How does the utricle communicate with the saccule
The utricosaccular duct
79
What are the sense organs within the utricle and saccule called
Maculae
80
What part of the vestibular floats on the endolymph
Otoliths
81
What do movements of the head cause the otoliths to do
To deflect the maculae, eliciting impulses
82
What does the utricle detect
Centrifugal and linear accelerations (in all planes)
83
What does the saccule detect
Linear accelerations in vertical and A/P planes
84
What are the sense organs in the semicircular ducts called and where are they located
Crista located in the ampulla of each duct
85
What are the semicircular ducts sensitive to
Any direction but particularly sensitive to rotational accelerations
86
Impulses initiated by crista are carried by neurons with cell bodies located wehre
Vestibular ganglion
87
What are the branches of dendrites carrying info to the vestibular ganglion
Inferior and superior branches
88
How many fibers are carried in the sup/inferior dendritic branches to the vestibular ganglion
Sup = 12,000 and inf = 8,000
89
The superior branch of the vestibular ganglion carries info from where
The anterior and lateral semicircular duct and the utricle, also some from the saccule (Voit’s) nerve
90
The inferior branch of the vestibular ganglion carries info from where
The posterior semicircular duct and the saccule
91
Axons from the vestibular ganglion make up the what
Vestibular nerve
92
What is the blood supply of the labyrinth
Internal auditor artery, and the stylomastoid artery
93
What is the sympathetic nerve supply to the labyrinth
From the cavernous and/or internal carotid plexuses
94
The cochlear nerve is composed of axons that send information through where
The cochlear to nuclei to the superior olivary/trapezoid nuclei located in the MO
95
Information from the superior olivary/trapezoid nuclei in the MO then is carried where
In the lateral lemniscus to inferior colliculi and medial geniculate body
96
After going through the lateral lemniscus and medial geniculate bodies information from cochlear nerve goes to where
The temporal lobe to reach brodmann areas 41 and 42
97
What is the vestibular nerve made up of axons from
The vestibular ganglion
98
Axons of the vestibular nerve carried to where
The vestibular nuclear complex of the medulla oblongata
99
After traveling to the vestibular nuclear complex of MO info is processed where of the vestibular nerve
In the cerebellum
100
What bones are located in the tympanic cavity
Malleus, incus, stapes
101
What bone in the tympanic cavity is the largest and what does it contact with
Malleus and contacts with the tympanic membrane
102
What does the incus transmit vibration from and to
From the malleus to the stapes
103
What tympanic cavity bone has its base against the oval window
The stapes
