ORGAN OF CORTI ::
The neuroepithelium of cochlea is known as organ of corti it is the sense organ of hearing It is situated on the basilar membrane and consists of two rows of cells outer and inner rods of corti or hair cells Basilar-membrane is a fibrous structure with about 29000 fibres running from the inner core or modiolus to the outer core core of bony tube It is about 32 mm in length The fibres of the membrane act as resonatory The vibrations of the basilar membrane is in the form of a wave The outer rods of corti lie on the basilar membrane whereas the inner rods of corti lie close to the osseous lamina There are about 3500 inner rods of corti and about 20000 outer rods of corti Inner and outer rods of corti are inclined to each other Each rod of corti has about 20 tiny hairs In between rods of corti there are supporting cells of Deites on the outer border of the spiral lamina there is tectorial membrane The nerve fibres enter the organ of corti from the modulus (pillar) The nerve fibres of the outer rods of corti cross the tunnel of Corti and join the nerve fibre from the inner hair cells and then meet the bipolar cells of spinal ganglia
The organ of corti resembles the musical instrument called piano The human ear can catch sound waves within limits Therefore man cannot perceive such sound notes as some birds do
The appreciation of these sounds take place in the auditory areas located in the temporal region of the cerebral cortex Interpretation of the sound takes place in the psychoauditory area which surrounds the auditory area in the brain
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