Describe the function of hair cells in the cochlea. The CNS 'knows' a stimulus is strong when the frequency of action potential generation is high. A stronger stimulus does not affect the degree of depolarization during an action potential, as an action potential is an 'all or none' phenomenon. Her symptoms suggest constriction of blood vessels in her fingers. Nicotine is a nicotinic acetylcholine receptor agonist, and it could therefore mimic acetylcholine's effect on sypathetic nicotinic receptors in the postganglionic neurons which innervate the skin's blood vessels.
Hair cells are the hearing mechanoreceptor cells, and they reside in the cochlea.
Sound waves are transmitted to the eardrum, then to the bones of the middle ear, and then to the oval window. This compression of the oval window causes compression waves of equal frequency in the cochlear fluid. When the hairs bend, this causes stretching of tip links between the hair rows, and this stretching is thought to open nonselective ion channels. The influx of cations such as sodium through these channels then causes depolarization of the hair cell.