hearing

• amplitude

  loudness
• wavelength

  pitch
• frequency

  period of cycles/sec
• what does conduction of sound waves to the inner ear rquire?

  mechanical vibrations
• what are the 3 bones of the inner ear?

  malleus, incus, stapes
• what are the auditory ossicles efficient at?

  amplifying sound waves (through tympanic membrane out oval window)
• what contains perilymph?

  scala vestibuli and scala tympani
• what is perilymph?

  high Na+/Ca2+, low K+
• what contains endolymph?

  scala media
• what is endolymph?

  low Na+/Ca+, high K+
• what does the organ of corti do?

  generates shear between hair cells and tectorial membrane when the BM moves up and down
• what do hair cells contain?

  sterocilia
• what are adjacent sterocilia connected by?

  tip links
• what is mechanotransduction?

  1) tip link pulls open K+ ion channel

  2) allows K+ to go down gradient

  3) causes depolarization in hair cell

  4) Ca+ channels open

  5) GLUT release (amplitude coding)
• what are proteins associated with tip links?

  cadherins and protocadherins
• how is the BM organized?

  tonotopic organization - continues to brainstem
• does the cochlea have a place code?

  yes - BM thick at base and thin at apez
• what is the base of the BM sensitive too?

  high frequencies
• what is the apex of the BM sensitive too?

  low frequencies
• what do outer hair cells demonstrate?

  electromotility - extend and contract which result in stiffness and sensitivity of cochlear partition
• what do auditory nerve axons demonstrate?

  phase locking - provides temporal code to sound frequency
• what is the volley principle?

  multiple neurons provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but not every period