Exam 2 - Audition Flashcards
3 stimulus properties of sound waves
pitch, loudness, timbre
Pitch
determined by frequency (Hertz, Hz), cycles per second
Loudness
Determined by amplitude (intensity). Greater amplitude means louder sound
timbre
determined by complexity and tonal quality. Like knowing the difference between instruments
Outer ear
captures, focuses, and filters sound. Has pinna and auditory canal
Pinna
Flesh, cartilage ear. sticks out from the side of the head. Captures, funnels, & amplifies sound. Helps w/ localizing sound. Amplifies sound into the Tympanic membrane
Auditory canal
channel for sound to travel through
Middle Ear
Hollow region behind the tympanic membrane that transfers vibrations. Converts air vibrations into mechanical movement. Important bc inner ear is filled with fluid & more force is needed to move fluid than air. Link between outer & inner ear. Has tympanic membrane, ossicles, oval window, and round window
tympanic membrane
aka the eardrum. transmits sound energy to middle ear. Damage to this structure impairs hearing, esp. low
frequency sounds
ossicles
“small bones.” convert air vibrations into mechanical movement. Has malleus (hammer) - attached to tympanic membrane, incus (anvil), stapes (stirrup) - bottom presses against membrane behind oval window, info from here to cochlea
oval window
opening in the bone surrounding the cochlea. receives vibrations from ossicles (specifically the stapes)
round window
membrane separating cochlear duct from middle-ear. Allows fluid in cochlea to move back and forth
Inner ear
includes cochlea which has the organ of corti
cochlea
Snail-shaped; filled with fluid; surrounded by bone. It important for auditory transduction (where energy transforms from soundwaves to action potentials), contains organ of corti. The cochlea has 3 sections
-Scala vestibuli (entrance stairway)
-Scala media (middle stairway)
-Scala tympani (tympanic stairway)
Organ of Corti
receptive organ in scala media. where auditory transduction takes place. The vibratory energy on the oval window causes basilar membrane to bend. Different regions respond to different frequencies of vibrations in the fluid. Consists of 2 parallel membranes and hair cells in between. 1. basilar membrane. 2. Tectorial membrane.
auditory transduction
Transforms energy from sound waves into APs (in the cochlea). Analyzes frequency of sound waves. Ex. pitch
Hair cells
located in between basilar membrane and tectorial membrane. Hair cells are anchored to the basilar membrane. Cilia are at the top of the hair cell. Synapse on bipolar neurons whose axons make up the auditory/cochlear nerve
tectorial membrane
“top shelf” against which the cilia move
Auditory transduction
- Sound waves cause vibrations/movement of basilar and tectorial membrane in cochlea.
- Cilia of the hair cells bend/are displaced.
- Receptor Potentials –> increased tension aka cilia movement can depolarize membrane, opening (calcium and potassium) ion channels in the cilia (bc of movement to tallest one). (does not necessarily mean AP is reached).
- Hair cells form synapses with axons of the cochlear (auditory) nerve bc of depolarization and moving over enough. Auditory nerve can trigger AP
- Action Potentials sent to the CNS/brain via the auditory nerve