Inner hair cells .E2.80.93 from sound to nerve signal Hair cell

section through organ of corti, showing inner , outer hair cells

the deflection of hair-cell stereocilia opens mechanically gated ion channels allow small, positively charged ions (primarily potassium , calcium) enter cell. unlike many other electrically active cells, hair cell not fire action potential. instead, influx of positive ions endolymph in scala media depolarizes cell, resulting in receptor potential. receptor potential opens voltage gated calcium channels; calcium ions enter cell , trigger release of neurotransmitters @ basal end of cell. neurotransmitters diffuse across narrow space between hair cell , nerve terminal, bind receptors , trigger action potentials in nerve. in way, mechanical sound signal converted electrical nerve signal. repolarization of hair cells done in special manner. perilymph in scala tympani has low concentration of positive ions. electrochemical gradient makes positive ions flow through channels perilymph.

hair cells chronically leak ca. leakage causes tonic release of neurotransmitter synapses. thought tonic release allows hair cells respond in response mechanical stimuli. quickness of hair cell response may due fact can increase amount of neurotransmitter release in response change little 100 μv in membrane potential.