The Auditory and Vestibular System Flashcards
Outer ear
collects sound waves and channels them into the ear canal,where the sound is amplified
Inner ear
Sense and process information about sound and balance, and send that information to the brain
Middle ear
Transmits sound from the outer ear to the inner ear
Bones of the middle ear
malleus, incus, stapes
Tympanic Membrane
Separates the outer ear from middle ear
What happens when sound waves reach the tympanic membrane? (3)
- They cause the membrane to vibrate.
- The vibrations are then transferred to the tiny bones in the middle ear.
- The middle ear bones then transfer the vibrating signals to the inner ear
What regions are located at the basal end of the cochlea?
oval window, round window
Oval Window
Connects the middle ear and inner ear, through which sound vibrations from stapes are transmitted.
Round Window
Allowing the movement of ear fluid within the cochlea, which results in the movement of the inner hair cells of the cochlea
What three fluid-filled channels are located within the cochlea
scala vestibuli, scala media, scala tympani
Which tube(s) in the cochlea is/are filled with perilymph?
scala vestibuli, scala tympani
Which tube(s) in the cochlea is/are filled with endolymph?
scala media
Difference between basilar and tectorial membrane
Basilar= Auditory receptor cells, called hair cells, lie embedded within the basilar membrane.
Tectorial membrane: Lies over the hair cells; it serves as a shelf against which the cilia of hair cells brush upon movement.
Organ of Corti
An organ of the inner ear located within the cochlea which produces nerve impulses in response to sound vibrations.
The organ of Corti (black) sits on a thin, flexible membrane called the ______ membrane (red) and under a relatively immobile membrane called the ______ membrane (blue).
basilar; tectorial
Stereocilia location
In the organ of corti and are embedded in the tectorial membrane
Function of stereocillia
Transform the mechanical energy of sound waves into electrical signals for the hair cells, which ultimately leads to an excitation of the auditory nerve.
The base of the basilar membrane (near oval window) is “tuned” for (LOW / HIGH) frequencies. This region of the membrane is (WIDER / NARROWER) and (LESS / MORE) flexible.
high; narrow and less
The apex of the basilar membrane (near helicotrema) is “tuned” for (LOW / HIGH) frequencies. This region of the membrane is (WIDER / NARROWER) and (LESS / MORE) flexible.
low; wider and more
Relationship between frequency and wavelength
The higher the frequency, the shorter the wavelengths and therefore the distance of travel is lower
Vertical movement of the basilar membrane is translated into?
Tectorial membrane moving across the tops of the hair cells, creating a shearing force that bends the sterocillia of the hair cells
Bending the stereocilia toward the kinocilium (upward phase) causes ______ and bending it away from the kinocilium (downward phase) causes __________
depolarization; hyperpolarization
mechanoelectrical transduction.
mechanisms by which cells convert mechanical stimulus into electrochemical activity.
What happens when the hair bundle is deflected toward the tallest stereocilium?
1) Cation-selective channels open near the tips of the stereocilia, allowing K+ to flow into the hair cell.
2)The resulting depolarization opens voltage-gated Ca+ channels in the cell soma, allowing the release of neurotransmitter onto the the nerve endings of the auditory nerve.