sensing the world - audition Flashcards
What are the main functions of hearing?
Detecting sound attributes (complexity, intensity, frequency) and locating the sound source.
What produces sound?
Vibrating objects displacing the surrounding medium (air or liquid), creating pressure changes.
What is frequency in sound perception?
The pitch; different animals detect different frequency ranges.
What is amplitude in sound perception?
The intensity or loudness of a sound.
Are complex sounds or pure tones more common in nature?
Complex sounds are more common; pure tones are rare
What is the role of the outer ear?
Captures and amplifies sound waves
What is the role of the middle ear?
Amplifies and transmits vibrations.
What is the role of the inner ear?
Translates vibrations into neural activity.
What are the three ossicles of the middle ear?
Malleus, Incus, and Stapes.
How do ossicles function in hearing?
They vibrate in response to the tympanic membrane and amplify sounds to the inner ear (oval window).
What is the Organ of Corti?
The structure containing hair cells that translate vibrations into neural signals.
What is basilar membrane tonotopy?
Spatial arrangement where different tones excite different regions of the basilar membrane.
What happens to pressure waves in the cochlea?
They deflect the basilar membrane frequency-specifically and dissipate through the round window.
What are the three canals of the cochlea?
Vestibular canal, Middle canal, Tympanic canal.
What does the tectorial membrane do?
Floats above the inner hair cells, touches outer hair cells, and bends stereocilia during vibration.
What are stereocilia?
Hair-like extensions on hair cells linked by tip links to potassium channels.
How is neural activity generated in hair cells?
Vibration bends stereocilia, increasing K+ influx, leading to increased neurotransmitter release.
What happens in hair cells in the absence of sound?
A basal K+ influx and low-level neurotransmitter release.
How is frequency coded in the cochlea?
By place coding—where the basilar membrane vibrates the most.
How is amplitude coded in the cochlea?
Louder sounds cause larger basilar membrane vibrations and greater neurotransmitter release.
What forms the auditory nerve (cranial nerve VIII)?
Bipolar cells activated by hair cell neurotransmitter release.
Where does the auditory nerve first project?
The medulla, maintaining a tonotopic map.
Where does auditory information ultimately end up?
In the primary auditory cortex (A1), preserving tonotopic organization.
What does hearing allow us to do?
Carry information about others and our environment.
