Question

in the auditory system, the sensory receptor is the cochlear hair cell. The resting Vm of the hair cells is around -70mV. The extracellular fluid around these cells has a very high concentration of K+. When the hair cells become permeable to K+, which direction will K+ travel and why? What impact will that have on the Vm of the hair cell? How does all of this differ from what we observe with K+ in our "typical" neurons.

Answer 1

The hair cells in the cochlea is surrounded by two fluid that are Endolymph and perilymph.

The apical part of the hair cell is surrounded by the Endolymph.The major ion present in the endolymph is potassium ion.This potassium ion help in carrying the current in th cochlea.

the base of the hair cell is surronded by the Perilymph.The amount potassium ion in th eperilymph is low compared to the endolymph.perilymph is rich in sodium cation

The hair cell is the sensory receptor in the cochlea. it is activated by the depolarization of the potassium channel.potaasium channel (transduction channel) are activated when there is a influx of potaasium ion in to the cell.

In an typical neuron , action potential is generated by the depolarization of the sodium channel resulting in the influof sodium ion and efflux of the potassium ion out of the cell.

But here the hair cell receptor is activated by the depolarization of potassium channel.

When the potassium ion enter the cell, it get activated and release the excitatory neurotransmitter called glutamate.

This neurotranmitter bind with the post synaptic receptor and the signal is transmitted to the auditory cortex through the Vestibulocochlear Nerve( 8th cranial nerve)