Auditory Flashcards
What is the Auditory System?
Determines the frequency, intensity and other properties of sounds
Interprets meaning of sound
Identifies source of sounds - sound localization
What is sound?
Audible variations in air pressure
- mechanical energy measured as the calculated pressure that a wave makes against an object (ear drum).
Sound Waves
Produced by vibrations of air molecules
Tonotopy
Mapping of sound frequencies on basilar membrane - Principle of adequate stimulus
Frequency Coding at Basilar membrane
Hair cells along basilar membrane have receptive fields differing in frequency preference
Frequency Coding or Tonotopy
Neural encoding of pitch (place codes)
Base of Basilar Membrane
Short and Stiff Fibers
Apex of Basilar Membrane
Long Floppy Fibers
Resonance
The tendency of a system to oscillate at a greater amplitude at some frequencies than at others.
Resonant Frequency
Small periodic driving forces can produce large amplitude oscillations because the system stores vibrational energy
High Frequency
Waves vibrate stiff fibers best (at base): travel short distance
Low Frequency
Waves vibrate floppy fibers best (at apex): travel entire distance
TRPA Channel
A family of transient receptor potential ion channels
- TRP channel blocks K+ ions and others @ tip links
- Stretch-activated channel opens when mechanically stimulated
Perilymph
In the Scala Vestibuli and Scala Tympani
Low K+, High Na+
Endolymph
In Scala Media
High K+, Low Na+
Endocochlear Potential
Endolymph is 80 mV more positive than perilymph