Audition Flashcards
Sound
Pressure waves of molecules in medium (ex. air)
Perception qualities include:
- Frequency
- Intensity/Amplitude
- Complexity
- Location
Functions of the ear include:
- Capture
- Mechanical transmission
- Conversion (electrical transduction and transmission)
The external/outer ear consists of:
- Pinna
- External auditory canal
Function of pinna?
- Collects and funnels sounds
- Enhances “shadowing” for localization
Function of external auditory canal?
Carries sound to middle ear
The middle ear consists of:
- Tympanic membrane
- Ossicles which consist of malleus (hammer), incus (anvil), and stapes (stirrup)
Function of middle ear?
Amplification
Concentrates surface area to amplify pressure, lever action of ossicles increases force
Tympanic membrane
- Flexible membrane (vibrates with sound waves)
- Border between outer and inner ear
Function of ossicles?
Conduct and amplify changes in air pressure
The stapes (stirrup) connects to:
Oval window of cochlea
The inner ear consists of:
- Oval window
- Vestibular apparatus
- Cochlea
- Round window
Function of vestibular apparatus?
Sense of acceleration in 3D and balance
Semi-circular canals
The three chambers of the cochlea are:
- Scala vestibuli
- Scala tympani
- Scala media
Shearing force on stereocilia created when
Hair cells move with sound and push against stationary tectorial membrane
Frequency/pitch coded by:
Location of max shearing
Intensity/loudness coded by:
Degree of hyper/depolarization (shearing)
Function of the Medial Geniculate Body (MGB)?
(of the thalamus)
- relays information from inferior colliculus (IC) to auditory cortex (AC)
- influences direction and maintenance of attention
- sound not consciously processed
Function of auditory cortex?
- conscious perception of sound
- sends information to secondary association areas for processing “what” and “where”
near Wernicke’s area (auditory association area) needed to understand speech
What does the anterior portion of the auditory cortex represent?
Apex of cochlea, low pitch
What does the posterior portion of the auditory cortex represent?
Base of cochlea, high pitch
Pathway of ascending auditory system from cochlea to brain?
Cochlear nucleus, superior olivary complex, inferior colliculus, medial geniculate nucelus, auditory cortex
