Frequency tuning curves(FTC) High intensity response to 1 10r (b) broader Hz range 100 10 mV 5 mVA 2 mv 80 70 50F Chat racteristic -20 40F frequency 30 20 Sharp ut-off 0 -20 5102030 Frequency(kfIz) Most sensitive Variation in sound intensity level is required to keep characteristic the intracellular receptor potential (mV) of a hair cell frequency constant at different frequencies Frequency
Frequency In c r e a sin g in t e n sit y Most sensitive = characteristic frequency Sharp cut-off High intensity = response to broader Hz range Frequency tuning curves (FTC) Characteristic frequency Variation in sound intensity level is required to keep the intracellular receptor potential (mV) of a hair cell constant at different frequencies Intracellular receptor potential{
Vestibular nerve Auditory Composition of the nerve cochlear fluids Oval Cross section of cochlea wIndow Scala Round Tectorial media window Cochlea membrane Scala media Scala contains endolymph vestibuli Spiral Scala vestibuli lio and Scala tympani Scala contain perilymph tympani Perilymph is similar to cerebro-spinal fluid and Inner other extra-cellular fluids: high in Na(150 mM hair cells Outer hair cells low in K+(3-4 mM), and Cat(0.6-1 mM membrane
Composition of the cochlear fluids Scala media contains endolymph Scala vestibuli and Scala tympani contain perilymph Perilymph is similar to cerebro-spinal fluid and other extra-cellular fluids: high in Na+ (150 mM), low in K+ (3-4 mM),and Ca+ (0.6 - 1 mM). Endolymph is low in Na+ (1-2 mM), high in K+ (150 mM), and very low in Ca+ (0.03 mM)