Stria vascularis in scala media secretes endolymph

Stria vascularis in scala media secretes endolymph. Ototoxic drugs like furosemide, bumetanide, ethacrynic acid cause oedema & cystic changes in stria vascularis causing hearing impairment. Quinine & chloroquine/hydroxychloroquine ototoxicity is due to vasoconstriction in the small vessels of stria vascularis.
Basilar membrane moves in response to vibrations sent into surrounding fluids during sound conduction (by footplate vibrations).
Organ of corti (structural and functional unit of hearing / peripheral receptor of hearing) lies on basilar membrane.
Outer hair cells and inner hair cells are present in organ of corti. These have small hair like stereocilia above their surfaces. They rub against the tectorial membrane above when basilar membrane moves in response to fluid vibrations set-up during sound conduction.
Aminoglycosides like neomycin, kanamycin, amikacin, sisomycin, dihydro-streptomycin and cytotoxic drugs like nitrogen mustard, cisplatin, carboplatin damage outer hair cells causing hearing impairment (cochleotoxic).
Potassium channels open up during rubbing and action potential gets generated and travels along the auditory fibres into the brain. That particular signal from auditory nerve is perceived by the brain as that particular sound.
Remember – this auditory nerve (cochlear) is entering the antero-inferior part of internal auditory canal.
Human cochlea can perceive sounds of frequency ranging 20Hz-20000Hz. (But much of the routine conversational frequencies will range between 500Hz-2000Hz only). Cochlea (scala media) connected to saccule by ductus reuniens.