Term
| What are the 4 major divisions of the auditory system? |
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Definition
| Outer ear, Middle ear, Inner Ear, and the Central Auditory Nervous System |
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Term
| What are 2 major components of the outer ear? |
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Definition
Pinna (aka Auricle): Protects and channels acoustic information into EAC and assists in sound localization
External Auditory Meatus (EAM) or External Auditory Canal (EAC): Directs sound towards tympanic membrane and provides some increase in sound intensity (resonator) and protects the TM |
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Term
| Where is the Tympanic membrane? |
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Definition
| -Located at the end of the EAM |
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Term
| What are the layers and regions of the TM? |
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Definition
-3 layers: Ectoderm, Mesoderm, and Endoderm
-2 regions: pars flaccida and pars tensa |
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Term
| What do vibrations tell us in the TM? |
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Definition
-Amount of TM vibration proportional to sound’s intensity
-Speed of vibration proportional to sound’s frequency |
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Term
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Definition
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Term
| What are the 3 parts of the Ossicular Chain and the 3 parts of the Windows? |
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Definition
Ossicular Chain: Malleus, Incus, Stapes
Windows: Oval, Round, Promontory |
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Term
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Definition
Air pressure of the middle ear must match that of the EAM
-Equal pressure on both sides of the TM maximizes mobility |
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Term
| What is the difference between ascent and descent? |
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Definition
-Ascent- air in the external ear canal becomes thin, while the middle ear remains at the ground level pressure
-The TM is pushed outward
-Descent- pressure in the middle ear may be less than the ear canal
-The TM is pushed inward |
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Term
| What are the 2 muscles in the middle ear? |
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Definition
Tensor Tympani muscle: Startle reflex
Stapedius muscle: Responds to loud sounds |
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Term
| What happens in the inner ear? |
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Definition
| Stapes footplate moves in and out of the oval window. This movement causes movement of cochlear fluids in all 3 channels. Movement of cochlear fluids causes cells in the scala media to “fire” and transmit the sound signal from the cochlea to the auditory nerve (VII Cranial Nerve) |
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Term
| What is the auditory nerve? |
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Definition
• VIII Cranial Nerve:
Auditory Portion and Vestibular Portion
• Transmits electrical sound signal from cochlea to brainstem |
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Term
| What are the 5 nuclei groups in the Auditory Brainstem Pathway? |
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Definition
• Cochlear Nucleus
• Superior Olivary
Complex
• Lateral Lemniscus
• Inferior Colliculus
• Medial Geniculate
Body |
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Term
| Central Auditory Nervous System |
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Definition
• Processing of speech information occurs throughout the central auditory nervous system.
• Primary location for processing occurs in the left temporal lobe in most humans. |
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Term
| Hemispheric Specialization |
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Definition
Right Hemisphere → Spatial Information
Left Hemisphere→ Language Center |
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