Chapter 9.3-Inner Ear Flashcards
Inner Ear Function
Translates sound pressure waves into neural signals that are then transmitted to the brain for processing and interpretation as sound.
What is the function of the inner ear analogous to?
Retina with respect to light wave in vision; both structures translate information carried by waves into neural signals
Cochlea Function
Converting sound vibrations into electrical signals that our brain can understand.
Structure of Cochlea
Contains the organ of corti and filled with watery fluids in three parallel canals
Tympanic Canal (Scala tympani): Location
Lower chamber of the cochlea extends from apex of the cochlea to the round window
Tympanic Canal (Scala tympani) Function:
Transmit sound vibrations that pass through the cochlea, ultimately leading to the round window, which is an opening that allows for the dissipation of pressure.
Vestibular Canal- scala vesitbuli: Location
Upper chamber of a cochlea, extends at the oval window at the base of the cochlea to the helicotrema at the apex
Scala Vestibuli Function
Transmit sound vibrations from the middle ear to the inner ear (cochlea through oval window) and plays a role in maintaining balance
Middle Canal(endolymph) - scala media: Location
Middle chamber of the cochlea
Scala media function
Houses the organ of Corti, which contains specialized hair cells that detect sound vibrations and convert them into electrical signals that are then transmitted to the brain for hearing.
What are both the tympani and vestibular canals filled with? And connected by?
Filled with perilymph and connected by a small opening called the helicotrema
Waht specalized tissue lines one side of the middle canal? What do these specalized tissues do?
Straia vascularis, maintain the right balance of charged ions in the endolymph to keep hair cells working at their best
What are the three canals of the cochlea that are separated by the two membranes?
1) Resinne’s membrane
2) Basilar membrane
Resinne’s membrane
Thin sheath of tissue separating the vestibular and middle canals in the cochlea
Basilar membrane
A plate of fibers that forms at the base of the cochlear partition and separates the middle and tympanic canals in the cochlear
How do travelling waves flow through the inner ear?
Travelling waves flow through the fluid in the vestibular canal, similar to a loudspeaker moving air to create sound waves.
What happens to pressure changes in the cochlea?
Pressure changes create a displacement or “bulge” in the vestibular canal from the base to the apex of the cochlea,
What happens if sounds are extremely intense?
Intense sounds pass through the helicotrema and back to the cochlear base through the tympanic canal, relieving pressure at the round window.
The function of the round window:
Acts as a relief valve, allowing the release of excess pressure remaining from extremely intense sounds, preventing damage to delicate structures.
Question: Where is the basilar membrane located?
Answer: It lies at the bottom of the middle canal.
Organ of Corti Function
Responsible for converting sound vibrations into electrical signals that our brain can interpret as sound.
Organ of Corti Structure
On the basal membrane of the cochlea that is composed of hair cells and dendrites of auditory nerve fibers
Hair cells:
Secialized cells in the inner ear that use their stereocilia to convert mechanical movements into neural signals sent to the brain.
Auditory Nerve:
nerve responsible for transmitting auditory information from the inner ear to the brain.
Sterocillia
Hair like extension of tips of hair cells in the cochlear that when flexed, initiate the release of neurotransmitters
Tecotiral membrane: Location
On top of the organ of Corti in the inner ear. It is a gelatinous structure that plays a crucial role in the process of hearing
Tectorial Membrane Function
Allows the hair cells in the inner ear to detect sound vibrations by bending their stereocilia back and forth when it moves in response to sound.
How does the tectorial membrane move?
The tectorial membrane moves sideways when the partition of the cochlea moves up and down.
What is the role of the tectorial membrane in hearing?
The tectorial membrane helps to convert sound vibrations into neural signals that are sent to the brain for hearing.
How is the tectorial membrane related to the basilar membrane?
The tectorial membrane rests on top of the organ of Corti, while the basilar membrane lies beneath it. Both membranes are involved in the process of converting sound vibrations into neural signals for hearing
Cochlear Partition
The combined basilar membrane, tectorial membrane, and organ of Corti, which are together responsible for the transduction of sound waves into neural signals.
Hair cells in the cochlear partiion convert _____ energy into _______ firing
sound pressure; neural firing
How do photoreceptors and stereocilia in the cochlea differ?
The retina has more photoreceptors compared to the number of stereocilia in each cochlea, and stereocilia are faster and more sensitive than photoreceptors.
What are stereocilia connected by?
Stereocilia in the cochlea are connected to each other by tiny filaments called tip links
How do our ears and eyes differ in their sensitivity to changes in light and sound?
Our ears are always ready for the slightest sound due to the high sensitivity and fast response of stereocilia, while our eyes may take some time to adjust to a fully dark environment due to the slower response of photoreceptors.
What is the result of depolarization in the hair cell?
What completes the process of translating sound waves into neural activity?
The firing of the auditory nerve fibers, triggered by the release of neurotransmitters from the hair cell, completes the process of translating sound waves into patterns of neural activity.
Summarize the process of hair cell activation:
It involves the deflection of stereocilia, opening of ion pores, influx of potassium and calcium ions, release of neurotransmitters, and firing of auditory nerve fibers.
What is mechanoelectrical transduction?
conversion of mechanical stimuli or vibrations into electrical signals or energy.
How does this mechanoelectrical transduction in hearing differ from phototransduction?
Depolarization in hearing does not await a cascade of biochemical processes such as those in photoactivation
