How do we hear Flashcards
Outline the main stages of hearing.
Hearing involves collection, conduction (acoustic energy), conversion (electrical energy), and comprehension.
What is impedance, and why is impedance matching important in the ear?
Impedance is the resistance to sound wave propagation. Impedance matching by the middle ear reduces sound reflection from air to the cochlear fluid, enabling efficient sound transmission.
How does the middle ear achieve impedance matching?
It uses the tympanic membrane (TM) to oval window area ratio, lever action of ossicles, and buckling action of the TM, amplifying sound by about 52 times
Describe the structure and function of cochlear hair cells in the inner ear.
There are 3 rows of outer hair cells for amplification and 1 row of inner hair cells as main signal transducers, converting acoustic energy to electrical signals
What is tonotopic arrangement in the cochlea?
Tonotopic arrangement means that different frequencies stimulate specific regions along the cochlea, allowing us to perceive pitch.
What are two common hearing tests, and how do they differ?
Audiometry (behavioral test) and Auditory Brainstem Response (ABR) testing (objective test) measure hearing ability and brain response to sound, respectively.
What is conductive hearing loss, and what are its potential causes?
Conductive hearing loss occurs when sound cannot efficiently pass through the outer or middle ear, caused by issues like otitis media, ossicle malformation, or blockage.
What is sensorineural hearing loss, and what causes it?
Sensorineural hearing loss is due to inner ear or neural damage and can result from noise exposure, aging, ototoxic drugs, or infections.
When are cochlear implants considered, and how do they function?
Cochlear implants are for profound hearing loss unresponsive to hearing aids, directly stimulating the spiral ganglion cells of the auditory nerve.
