Unit 2: Auditory System Flashcards
1
Q
The pinna (auricle), external auditory meatus and external auditory canal makes up the ______ ear.
A
External ear
2
Q
The function of the external ear is to:
A
Collect sound waves
3
Q
The tympanic membrane and ossicles make up the ____ ear or ____ cavity
A
Middle; tympanic
4
Q
Malleus bone is attached to:
A
Tympanic membrane
5
Q
Incus articulates with
A
Malleus and stapes
6
Q
What covers the oval window?
A
Footplate of stapes
7
Q
The oval window is also called the
A
Fenestra vestibuli
8
Q
The round window is called the
A
Fenestra cochlea
9
Q
The tensor tympani muscle is innervate by
A
CN V
10
Q
Stapedius m innervate by
A
CN VII
11
Q
What is the function of the tensor tympani and stapedius?
A
Protect against sudden, excessive noice by contracting to dampen/lessen movements of tympanic membrane and ossicles.
12
Q
The osseous labyrinth and membranous labyrinth makes up the ____ ear
A
Inner ear
13
Q
Auditory and vestibular receptors are located within:
A
Inner ear
14
Q
Series of interconnected tunnels within petrous portion of temporal bone
A
Osseous labyrinth
15
Q
Space inside the osseous labyrinth is called:
A
Perilymphatic cavity
16
Q
Perilymphatic cavity is filled with
A
Perilymph
17
Q
Cochlea
A
“Snail” in Greek
18
Q
Where are the 3 semicircular canals?
A
Osseous labyrinth
19
Q
The interconnecting membranous tubes is filled by:
A
Endolymph
20
Q
Where are the 3 semicircular ducts?
A
Membranous labyrinth
21
Q
2 membranous dilations within the vestibule of the membranous labyrinth
A
Utricle and saccule
22
Q
The cochlear duct is located within the
A
Cochlear canal of the cochlea
23
Q
Scala media (aka cochlear duct) is located where?
A
Middle space of cochlear canal
24
Q
Scala vestibuli is located where?
A
Superior to scala media within cochlear canal
25
Where is the scala tympani located?
Inferior to scala media inside the cochlear canal
26
What space in the cochlear canal is filled with endolymph?
Scala media (AKA cochlear duct)
27
What space in the cochlear canal is filled with perilymph?
Scala vestibuli and Scala tympani
28
Continuous with the round window and the 2˚ tympanic membrane:
Scala tympani
29
Helicotrema
Helico “spiral”
Trema “hole”
Located at the apex of the cochlea and makes Scala tympani continuous with Scala vestibuli
30
What produces endolymph?
Stria vascularis
31
Damage to basal turn of the cochlea will harm what sound?
High frequency sounds (20,000 Hz)
32
Damage to the apical end of cochlea will harm what kind of sound?
Low frequency
33
The cochlear duct (AKA Scala media) is a membranous duct suspended in the middle of the cochlear canal. It has three walls/borders. What are they?
- vestibular membrane = Reissner’s membrane
- stria vacularis = outer wall
- basilar membrane
34
What is the membrane that separates the Scala media from the Scala vestibuli?
vestibular membrane = Reissner’s membrane
35
What is the membrane that separates the scala media from the scala tympani?
basilar membrane
36
What part of the cochlear duct (AKA Scala media) includes the organ of Corti?
Basilar membrane
- extends continuously along the spiral turns of the cochlear duct (basilar membrane)
- extends from basal turn to the distal end of the cochlea
37
What is the Organ of Corti?
specialized mechanoreceptor for auditory information: monitors physical and mechanical changes
38
What are the support cells of the Organ of Corti?
- border cells
- phalangeal cells
- pillar cells
- cells of Hensen
39
What is the tectorial membrane?
gelatinous membrane continuous along the organ of Corti where the tips of the hair cells are embedded
40
The sensory cells of the organ of Corti are also called hair cells. There are two types. What are they?
Inner hair cells
| Outer hair cells
41
Which sensory cells of the Organ of Corti are arranged in a single row and each engages at its base with terminals of fibers of the cochlear division of the VIII nerve?
Inner hair cells
42
Which sensory cells of the Organ of Cori are arranged in multiple rows with each cell innervated by fibers of the cochlear nerve?
Outer hair cells
43
The ‘hairs’ (sensory cells) of the Organ of Corti are modified ______ that extend from the apical end of the cells and are embedded into the __________.
- microvilli
| - tectorial membrane
44
What happens to the hair cells when the basilar membrane vibrates?
- the hairs bend in relation to the tectorial membrane - this activates mechanically sensitive ion channels
- this changes the excitability of the hair cells and generates auditory information relayed in the sensory fibers of cochlear neurons of the cochlear nerve
45
movement of the foot plate of the stapes at the______ window initiates corresponding pressure waves in the______ beginning at the vestibule
- oval
| - perilymph
46
The pressure waves created by the movement of the foot plate of the stapes at the oval window will propagate through which structure?
scala vestibuli, the
vestibular membrane, the endolymph in the cochlear duct and then initiate movement of the secondary tympanic membrane covering the round window and the basilar membrane
47
The specific part of the basilar membrane that vibrates maximally is dependent upon what?
the pitch of the sound (i.e.
| frequency)
48
The organ of Corti is tonotopically organized. What does this mean?
high pitch sounds are monitored along the basal turn of the cochlea while low pitch sounds are monitored near the apical end
49
What is the result of repeated exposure to excessively loud noises?
hairs of the hair cells will be sheared off
50
What part of the Organ of Corti is most vulnerable to damage due to loud noises? Why?
basal turn is the most vulnerable because regardless of
| frequency, it vibrates and can therefore result in high frequency deafness
51
Primary cochlear (auditory) neuron cell bodies are found where?
spiral ganglia (aka cochlear ganglia) positioned in spiral fashion in the modiolus along the turns of the cochlear duct.
52
The peripheral processes of primary cochlear (auditory) neurons innervate what?
Hair cells
53
The myelinated central processes of primary cochlear (auditory) neurons are included in what nerve?
cochlear division of the VIII nerve (vestibulocochlear nerve)
54
The central process of primary cochlear (auditory) neurons included in the cochlear division
of the VIII nerve and traverse what structure to reach the brainstem?
the internal acoustic meatus
55
The central processes of primary cochlear (auditory) neurons terminate in the rostral brainstem in one of two nuclei. What are they?
- (dorsal) cochlear nucleus
| - (ventral) cochlear nucleus
56
Secondary cochlear (auditory) neuron cell bodies are found where?
(ventral and dorsal) cochlear nuclei
57
Processes of the secondary cochlear (auditory) neuron cell bodies project rostrally through the central auditory pathway and include:
contralateral and ipsilateral projections (bilateral p/way) therefore, the ascending auditory pathway is bilateral and determines that auditory information that originated from one
ear is projected to auditory cortex in both cerebral hemispheres
58
Decussating fibers of the contralateral cochlear pathway are called what?
Trapezoid body
59
Secondary neurons of the contralateral auditory pathway project axons to the contralateral side of the _______ and some of them terminate in the contralateral _______ while others ascend in the __________ and terminate in the ________.
- Pons
- superior olivary nucleus
- lateral meniscus
- inferior colliculus
60
Fiber from neurons of the inferior colliculus traverse the inferior brachium and terminate in the _______ of the thalamus
- medial geniculate body
61
neurons of the medial geniculate body project axons through the __________. These fibers form the _______ and terminate in ________ in the temporal lobe
- posterior limb of the internal capsule
- auditory radiations
- primary auditory cortex
62
Some secondary cochlear (auditory) neurons in the (ventral) cochlear nucleus project axons rostrally to the ipsilateral___________. From there, the pathway is the same as for the fibers that decussate.
superior olivary nucleus
63
Where is the primary auditory cortex located
the floor of the lateral sulcus along the superior temporal gyrus specifically on Heschel’s gyrus (AKA anterior transverse temporal gyrus)
64
The primary auditory cortex corresponds to what Brodmann’s map areas?
41, 42
65
The primary auditory cortex has what kind of organization?
Tonotopic, i.e. different frequencies are processed in different locations
66
Low frequency sounds are processes in what portion of the primary auditory cortex?
Anterolateral region of the transverse temporal gyrus
67
High frequency sounds are processed in what portion of the primary auditory cortex?
Posteromedial region of the transverse temporal gyrus
68
What anatomical areas are included in the auditory association cortex?
regions of the temporal lobe that immediately surround Heschl’s gyrus
69
The auditory association cortex corresponds to what Brodmann’s map area?
22
70
What is the function of the auditory association cortex?
permits recognition and interpretation of sounds
| based on one’s previous experience with sound
71
Unilateral damage to auditory pathway structure above the cochlear nuclei would result in what?
slight hearing loss in both ears
72
Unilateral damage to the cochlear nuclei or any auditory structure peripheral to the nuclei would results in what?
hearing loss or decrease in hearing of the ipsilateral ear
73
Conductive hearing loss is due to what?
disturbances of the peripheral auditory receptor apparatus
74
Neural (sensorineural) hearing loss is due to what?
interruption of the VIII nerve or elements of the central pathway in the brain
75
Name two techniques for testing the integrity of the auditory system.
- Weber test
- Rinne test
NOTE: Details of these will be taught in other classes
76
Neurons of the inferior colliculi share connections with superior colliculi. In the auditory system, this connection allows for:
- physical reactions to startling sounds
- localization of sound
- intensity of sound
