Quiz #9 Flashcards
(23 cards)
1
Q
Peripheral auditory system
A
outer ear, middle ear, inner ear, CN VIII
2
Q
Middle ear
A
- part of peripheral auditory system
- acoustic energy hits the tympanic membrane (TM)
- TM begins to vibrate, indicating an energy change (acoustic energy)
- this mechanical energy is transmitted through the ossicles (malleus, incus, stapes)
- footplate of stapes rocks in/out of oval window
3
Q
Inner ear
A
- part of peripheral auditory system
- the rocking of stapes creates a wave in the cochlear fluids
- another energy change: mechanical energy has been changed into hydraulic energy
- waves disrupt the hair cells in the organ of Corti causing a third energy change: hydraulic energy changed to electrochemical energy
4
Q
Nerve conduction
A
- part of peripheral auditory system
- brainstem and brain
- cochlear branch of CN VIII connects into the hair cells of the organ of Corti
- this nerve conducts the electrochemical impulse to the brainstem
5
Q
Central auditory system
A
brainstem and brain
6
Q
Brainstem organization: CNC
A
- part of central auditory system
- CN VIII inputs into the brainstem’s cochlear nuclear complex (CNC), aka cochlear nucleus (CN), an area of specialized cells for auditory information
- the cochlear nucleus lies where the pons and medulla meet at cerebellopontine angle
- where vestibular and cochlear branches of CN VIII diverge
7
Q
Brainstem organization: cochlear nucleus
A
- part of central auditory system
- the cochlear nucleus processes incoming auditory signals by differentiating frequencies and timing information which is critical for sound localization
8
Q
Brainstem organization: lateral leminiscus
A
- part of central auditory system
- a prominent fiber bundle/tract in midbrain that plays a role in auditory pathway
9
Q
Brainstem organization: inferior colliculi
A
- part of central auditory system
- inferior colliculi = auditory center of midbrain
- maintains tonotopic organization that originated in the cochlea
- important for localization of sound, pitch discrimination
- regulates the acoustic starter reflex, our sudden movement when an unexpected sound occurs
10
Q
Diencephalon organization: MGB
A
- part of central auditory system
- medial geniculate body (MGB)
- auditory center of the thalamus
- acts as a relay station that relays auditory tracts to the auditory parts of the cerebral cortex
- lateral geniculate body in the thalamus is the visual center
11
Q
Cerebral cortex organization: PAC
A
- part of central auditory system
- central auditory pathway ends at primary auditory cortex (PAC)
- the PAC found on the superior temporal gyrus (Herschl’s gyrus)
- tonotopically organized, like the cochlea and the rest of the central auditory system
- functionally, perceives and discriminates sounds
12
Q
Peripheral vestibular system
A
semicircular canals and CN VIII
13
Q
Semicircular canals
A
- part of peripheral vestibular system
- three fluid-filled canals that correspond to our 3D world
14
Q
Anterior SCC
A
coronal plane of space
15
Q
Posterior SCC
A
sagittal plane of space
16
Q
Horizontal SCC
A
transverse plane of space
17
Q
Ampulla
A
- part of peripheral vestibular system
- each SCC has a swelling called ampulla
- inside each ampulla is the structure known as crista
- cristas have hair cells similar to the cochlea
- these hair cells are sensitive to body movements in the different planes of space
18
Q
Utricle & saccule
A
- part of the peripheral vestibular system
- the vestibule of the vestibular system is located in the bony brain labyrinth between cochlea and SCC’s
- the utricle and saccule are found in the vestibule
- each has a sensory epithelium called the macula
- within macula are hair cells that have calcium carbonates crystals embedded in a gelatinous membrane
- displacement of these crystals impact balance via impact on cerebellum and eyes
19
Q
Central vestibular system
A
brainstem and brain
20
Q
Generation of nerve impulse
A
- part of central vestibular system
- two types of hair cells: stereocilia and kinocilia
- with body movement, fluids move in SCC
- if stereocilia bend toward kinocilia, hair cell depolarizes and signal goes to brain (if bends away = inhibition, no signal sent to brain)
21
Q
Vestibular nuclei: cerebellum
A
- part of central vestibular system
- vestibular nuclei projects fibers to the cerebellum
- three vestibular nuclei-to-cerebellum connections facilitate the coordinated movements necessary to preserve the body’s balance
22
Q
Vestibular nuclei: eye movements
A
- part of central vestibular system
- vestibular nuclei projects fibers to nuclei in brainstem (pons) that control eye movements
- nuclei include abducens nucleus in pons; trochlear nucleus in midbrain; oculomotor nucleus in midbrain
23
Q
Vestibulo-ocular reflex (VOX)
A
keeps eyes fixed/stable (visual field and retinal image) when moving head
