vestibular and auditory Flashcards
(133 cards)
1
Q
what CN is involved in the vestibular and auditory system?
A
CN VIII - vestibulocochlear nerve
2
Q
where does CN VIII (vestibulocochlear nerve) exit the skull?
A
internal acoustic meatus
3
Q
what two nerves exit through the internal acoustic meatus?
A
CN VIII - vestibulocochlear nerve
CN VII - facial nerve
4
Q
vestibular system detects (2)
A
head movement
position
5
Q
vestibular system is essential for (3)
A
posture
stability
coordination
6
Q
where is the vestibular system located?
A
inner ear within the petrous part of temporal bone
7
Q
vestibular system is composed of
A
semicircular canals
utricle
saccule
8
Q
semicircular canals detect
A
angular motion
9
Q
utricle detects
A
horizontal acceleration
10
Q
saccule detects
A
verticle acceleration
11
Q
semicircular canals are at ____ angles to each other. how many bony canals?
A
right angles
3: anterior, lateral, posterior
12
Q
what are the swellings at the bases of semicircular canals called?
A
ampullae
13
Q
How many sensory receptors are in the vestibular system?
A
5:
ampullae (3)
utricle
saccule
14
Q
ampullae detect
A
rotational movement
15
Q
within each ampullae, there is a receptor organ called the
A
crista ampullaris
16
Q
crista ampullaris
A
receptor organ within the ampullae
composed of hair cells and senses motion in the head
17
Q
crista ampullaris senses
A
motion in the head
18
Q
in the lateral semicircular canal, if the head turns to the right, the culpa
A
turns to the left
19
Q
the culpa’s movement is ____ to the head movement
A
oppositive
20
Q
semicircular canal movements:
lateral:
anterior:
posterior:
A
lateral: shake “no”
anterior: shake “yes”
posterior: side to side “maybe”
21
Q
otoliths are like
A
crystals
22
Q
where are otoliths located?
A
utricle and saccule
23
Q
otoliths are displaced during
A
head acceleration
24
Q
otoliths are displaced during acceleration and the ciliary bundles of the hair cells are deflected, then what?
A
sensory signal in CN VIII
25
benign paroxysmal positional vertigo
vestibular disorder caused by dislodges otoliths from the utricle into the semicircular canals
26
what are otoliths made of
calcium carbonate crystals
27
Free-floating otoliths in the semicircular canals disrupt normal fluid dynamics, sending false signals of motion to the brain
benign paroxysmal positional vertigo
28
symptoms of vertigo
Dizziness, nausea, and imbalance
29
where do signals from the vestibule travel to first?
vestibular nuclei in the brainstem
*junction of pons and medulla
30
the vestibular nuclei integrate input from what?
vestibular apparatus
visual system
proprioception
31
from the vestibular nuclei, where do signals get sent to? (4)
cerebellum
thalamus
spinal cord
oculomotor nuclei
32
function of processing regions after the signal gets sent from the vestibular nuclei
cerebellum:
thalamus:
spinal cord:
oculomotor nuclei:
cerebellum: balance and coordinates movement
thalamus: balance and spatial orientation
spinal cord: posture and balance (via vestibulospinal tracts)
oculomotor nuclei: eye movements to maintain a stable visual field during. movements *vestibulo-ocular reflex (medial longitudinal fasciculus (MLF))
33
cerebellum does what with signals from vestibular nuclei?
fine-tunes balance and coordinates movement
34
thalamus does what with signals from vestibular nuclei?
Relays vestibular information to the cortex for conscious awareness of balance and spatial orientation
35
spinal cord does what with signals from vestibular nuclei?
Influences motor neurons via the vestibulospinal tracts, maintaining posture and balance
36
oculomotor nuclei does what with signals from vestibular nuclei?
Via the medial longitudinal fasciculus (MLF), coordinates eye movements to maintain a stable visual field during head movements (vestibulo-ocular reflex)
37
vestibulo-ocular reflex via what?
medial longitudinal fasciculus (MLF)
coordinates eye movements to maintain a stable visual field during head movements
38
Cortical Processing
Signals reach the vestibular cortex, located in the parietal and insular regions of the brain, for conscious perception of motion and spatial orientation.
39
reflex pathways of the vestibular system
vestibulo-ocular reflex (VOR)
vestibulospinal reflex
40
vestibulo-ocular reflex (VOR)
Stabilize vision by coordinating eye movements with head movements
41
vestibulospinal reflex
Adjust body posture to maintain balance
42
if the head is turning to the right, causing the semicircular canals to move, what is activated?
right vestibular apparatus
43
once the fluid in the semicircular canal excited the hair cells, the signal is sent through the ____ to the ____
vestibular nerve to the vestibular nucleus
44
after the signal is sent to the vestibular nucleus, it travels to the (2)
abducens nucleus (pons)
oculomotor nucleus (midbrain)
*via medial longitudinal fasciculus (MLF)
45
From the vestibular nucleus, signals travel to the abducens nucleus (pons) and the oculomotor nucleus(midbrain) via the ___
medial longitudinal fasciculus (MLF)
46
the lateral rectus muscle is activated via the
abducens nerve (CN VI)t
47
The medial rectus muscle is activated by the
oculomotor nerve (CN III)
48
lateral rectus muscle is activated by the ----->
medial rectus muscle is activated by the ----->
lateral rectus muscle is activated by the -----> abducens nerve CN VI
medial rectus muscle is activated by the -----> oculomotor nerve CN III
49
auditory system
detects sound waves and converts them into electrical signals for processing by the brain
50
the auditory system is essential for
hearing, communication, and environmental awareness
51
three parts of the auditory system
external ear
middle ear
inner ear
52
external ear functions
collect and funnel sound waves
protect tympanic membrane
*external acoustic meatus
53
eardrum is the
tympanic membrane
54
auricle aka
pinna
55
middle ear functions
amplify and convert sounds into mechanical energy
provide pressure release
56
where is the middle ear located?
in petrous part of temporal bone
57
What is the middle ear continuous with?
Continuous with nasopharynx via auditory tub (aka pharyngotympanic tube, Eustachian tube)
58
auditory ossicles are what?
extremely dense bones covered in mucous membrane (not periosteum)
synovial joints
59
what do auditory ossicles do?
conducts vibrations from tympanic membrane to fluid-filled chamber of cochlea, via oval window
60
what type of joint are the auditory ossicles?
synovial joints
61
what are the three auditory ossicles?
malleus
incus
stapes
62
Manubrium of the malleus is
embedded in tympanic membrane
63
what is the smallest and lightest bone in the human body?
stapes
64
Change in size between tympanic membrane and footplate means vibration increases ___ in pathway through the ossicles
10x
65
66
67
middle ear infection that causes inflammation and fluid build-up
acute otitis media
68
acute otitis media can cause blockage of
pharyngotympanic tube
69
acute otitus media child vs adult
in children: Eustachian tubes are smaller and more horizontal, which makes it more difficult for fluid to drain out of the ear.
70
inner ear functions
Receive mechanical energy and convert into fluid wave
Respond to fluid waves for proprioception of sound
71
inner ear is located
in otic capsule in petrous part of temporal bone
72
sensory organs of inner ear
cochlea
vestibular apparatus
73
cochlea:
vestibular apparatus:
cochlea: hearing
vestibular apparatus: balance
74
75
path of sound
pinna (auricle)
external acoustic meatus
tympanic membrane
malleus
incus
stapes
oval window
fluid inside cochlea
76
When sound waves cause the stapes to move, they generate ___ waves in
the perilymph of the scala vestibuli
pressure
77
When sound waves cause the stapes to
move, they generate pressure waves in
the
perilymph of the scala vestibuli
78
Pressure waves initiated in the scala vestibuli pass through the ___ ___ and into the scala tympani
cochlear duct
79
Pressure waves initiated in the scala vestibuli pass through the cochlear duct and into the ___ ___
scala tympani
80
pressure waves end in the scala tympani where they are eventually relieved at the
round window
81
Vestibular membrane
Separates the scala vestibuli from the cochlear duct
barrier to maintain the distinct ionic composition of the endolymph in the cochlear duct
82
Basilar membrane
Separates the scala tympani from the
cochlear duct
structural support for the organ of Corti and is crucial for translating sound waves into neural signals
83
tympanic membrane separates:
basilar membrane separates:
tympanic membrane separates: scala vestibuli from cochlear duct
basilar membrane separates: scala tympani from the cochlear duct
84
Tectorial membrane
Facilitate the deflection of hair cell stereocilia by creating a shearing force during cochlear vibrations. This motion opens ion channels in the hair cells
85
Organ of Corti
Houses inner and outer hair cells, supporting cells, and the tectorial membrane, functioning as the primary site for sound wave transduction into neural impulses
86
Hair cells in the cochlea
Sensory cells in the cochlea that convertmechanical vibrations into electrical signals and amplify vibrations to enhance hearing sensitivity and clarity
87
88
cochlea pitch locations
base: high pitch
apex: low pitch
89
human hearing range is generally between
20-20K Hz
90
hertz
"Hz" (hertz) measures the frequency of a sound, which determines its pitch (how high or low it sounds)
91
decible
"Decibel" (dB) measures the intensity of a sound, indicating its loudness
92
electrical signals from the hair cells of the cochlea are transmitted via the
cochlear nerve
93
cochlear nerve is a branch of the
vestibulocochlear nerve CN VIII
94
the cochlear nerve transmits signals to where first?
cochlear nuclei
95
the ventral and dorsal cochlear nuclei are located in the
rostral medulla
96
cochlear nerves synapse in the
the ventral and dorsal cochlear nuclei
97
Dorsal acoustic stria:
Carries signals directly to higher auditory centers
98
Intermediate acoustic stria:
Part of the processing route from the dorsal cochlear nucleus.
99
what are the two pathways following the synapse in the cochlear nuclei?
dorsal acoustic stria
intermediate acoustic stria
100
dorsal acoustic stria
carries signals directly to higher auditory centers
101
intermediate acoustic stria
part of the processing route from the dorsal cochlear nucleus
102
dorsal acoustic stria vs intermediate acoustic stria
Dorsal acoustic stria: Carries signals directly to higher auditory centers.
Intermediate acoustic stria: Part of the processing route from the dorsal cochlear nucleus.
103
some fibers from the ventral cochlear nucleus project to the ___ ____ ____ via the trapezoid body
superior olivary complex
104
Some fibers from the ventral cochlear nucleus project to the superior olivary complex via the
trapezoid body
105
where does sound localization begin? (determining direction of sound)
from the ventral cochlear nucleus project to the superior olivary complex via the trapezoid body
106
superior olivary complex is critical for _____ hearing (processing inputs from both ears)
binaural
107
how do signals travel after the superior olivary complex?
via lateral lemniscus
*a fiber tract that transmits auditory information to the midbrain.
108
the lateral lemniscus is a fiber tract that transmits
auditory information to the midbrain
109
the lateral lemniscus transmits auditory info from the ___ to the ___
superior olivary complex to the midbrain
110
what connects the superior olivary complex to the midbrain (tract)?
lateral lemniscus
111
what nucleus is responsible for refining timing and amplitude data?
nucleus of the lateral lemniscus
112
all auditory fibers converge at the ___ in the mid-brain
inferior colliculus
113
where is the inferior colliculus located?
midbrain
114
what does the inferior colliculus do?
integrates spatial and spectral sound info and coordinates auditory reflexes
*where all auditory fibers converge in the midbrain
115
from the inferior colliculus, signals go to what? and where is it located?
medial geniculate nucleus (MGN)
in the thalamus
116
the medial geniculate nucleus acts as a ____ station
relay
117
where does refining of the auditory signals AND preparing for higher-order processing occur?
at the medial geniculate nucleus
118
what is the final destination of auditory signals?
primary auditory cortex in the temporal lobe
119
where does sound perception occur (including recognizing pitch, tone, and location)?
primary auditory cortex
120
auditory pathway locations (10)
1. Cochlear hair cells
2. Bipolar Cells of Cochlear Ganglion
3. Cochlear Nerve (branch of CN VIII)
4. Cochlear Nuclei
5. Trapezoid Body
6. Superior Olivary Nuclei
7. Lateral Lemnisci
8. . Inferior Colliculi
9. Medial Geniculate Bodies
10. Primary Auditory Cortex
121
122
123
124
The utricle and saccule in the vestibular system primarily detect which type of movement?
Vertical and horizontal linear acceleration
125
Damage to one lateral lemniscus does not result in complete hearing loss. Which feature of the auditory pathway prevents total loss of hearing in this case?
Crossed and uncrossed projections in the cochlear nuclei
126
A patient reports dizziness and hearing loss on the left side. Examination reveals a drooping left eyelid and reduced taste sensation on the left anterior tongue. Imaging shows a mass compressing cranial nerves VII and VIII. Which structure is most likely affected?
Internal acoustic meatus
127
A malfunction in which vestibular structure would impair detecting vertical motion, such as ascending or descending in an elevator?
saccule
128
Which part of the cochlear basilar membrane is most sensitive to high-frequency sounds?
the base, which is narrow and stiff
129
A tennis player struggles to track the ball during a fast rally, reporting dizziness and blurred vision with side-to-side head movements. Which vestibular structure is most likely affected?
horizontal (lateral) semicircular canal
130
A child presents with muffled hearing and a sensation of fullness in the ears after a cold. Examination reveals a bulging tympanic membrane without perforation. Dysfunction of which structure most likely contributed to this condition?
eustachian tube
131
A runner notices increased unsteadiness when running downhill. Testing reveals impaired detection of linear acceleration. Which vestibular structure is most likely damaged?
utricle
132
The vestibulo-ocular reflex is essential for which function?
stabilizing vision during head motion
133
A 45-year-old woman experiences episodic vertigo and hearing loss. Examination reveals diminished taste sensation on the anterior two thirds of her tongue and difficulty closing her right eye. Which structure is most likely affected?
internal acoustic meatus
