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Intro Audiology
Intro to Audiology Ch 1
Term | Definition | Function |
---|---|---|
Pinna (auricle) | visible part of the outer ear made up of cartilage | collects sound waves (energy) and conducts them to the ear canal |
Sound Waves | Airborn signals that travel through the outer ear. | |
Ear Canal | a tube running from the outer ear to the middle ear (part of the outer ear) | conducts sound waves(energy) to the ear drum |
Outer Ear | External portion of the ear consisting of the Pinna and ear canal. | focuses sound on the ear drum |
Ear drum | (Tympanic membrane) a thin membrane that vibrates when sound waves reach it | divides the outer and middle ear |
Middle Ear | contains three ossicles | couples vibration of the eardrum into waves in the fluid and membranes of the inner ear |
Ossicles | the three smallest bones in the human body (malleus, incus,and stapes) | transmit sounds from the air to the fluid-filled cochlea |
Incus (anvil) | a tiny bone that passes vibrations from the malleus (hammer) to the stapes (stirrup) | |
Cochlea | a spiral-shaped, fluid-filled (sensory cells) inner ear structure | it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form (for hearing) |
Eustachian tube | a tube that connects the middle ear to the back of the nose (nasopharynx) | it equalizes the pressure between the middle ear and the air outside. |
Malleus (hammer) | a tiny bone that passes vibrations from the eardrum to the incus (anvil). | |
Auditory nerves | (VIIIth cranial nerve) | carry electro-chemical (acoustic) signals from the inner ear (the cochlea) to the audiocortex of the brain |
semicircular canals | three loops of fluid-filled tubes that are attached to the cochlea in the inner ear | they help us maintain our sense of balance |
Stapes (stirrup) | a tiny, U-shaped bone. This is the smallest bone in the human body | passes vibrations to the cochlea |
Audiology | The science of hearing | |
how does sound travel | Sound is collected by the pinna and directed through the ear canal this vibrates the eardrum, which causes the ossicles to vibrate. The vibration is transferred to the cochlea which triggers the generation of nerve signals that are sent to the brain. | |
peripheral hearing loss | affects periphery of hearing structure (conductive, sensory, mixed) | |
conductive hearing loss | outer ear, ear drum, or middle ear damage (normal bone hearing, loss by air hearing) | mostly treatable loss caused by ear wax, swollen canal due to infection caused by diseases or obstructions in the outer or middle ear |
sensory hearing loss | damage to cochlea or 8th cranial nerve (hearing loss by air & bone conduction) | rarely treatable loss caused by tumor, measles or loud music |
mixed hearing loss | conductive and sensory damage in the SAME ear (bone hearing loss, greater air loss) | |
central hearing loss | damage to brain stem or auditory cortex | some causes are aids or alzheimers |
bone conduction hearing | the conduction of sound to the inner ear through the bones of the skull. sound goes directly to the cochlea bypassing the outer and inner ear | how people hear their own voices |
air conduction hearing | conduction of sound through the ear canal |