It consists of the inner ear, cochlea and vestibular system. The bone labyrinth of the inner ear, which consists of a bone labyrinth and membranous labyrinth, consists of the vestibule, the semicircular canals and the bone cochlear canal. It wraps 2-3 / 4 times on itself and ends in apex.
The central vertical axis is called modiolus and this structure acts as an interior wall. The spiral channel of the cochlea has a length of about 35 mm and is divided into two parts by the bone spiral lamina based on the inner wall along its entire length.
There are 3 tubular structures inside the cochlea and these structures contain liquids. When these structures are listed from top to bottom:
1. Scale Vestibuli
2. Scale Media (cochlear duct)
3. Scale Timpani
Skala vestibuli and scala tympani combine at the top and form the structure called heliotrema. Scale media ends with a closed tip in a heliotrema.Skala vestibuli and scala tympani are filled with a high sodium content and low potassium fluid called perilenf.
Scale media is filled with endolymph fluid secreted by stria vascularis, high in potassium and low sodium. While the scale media and the scale vestibuli are separated from each other by the Reissner’s membrane, the scale media and the scale tympani are separated by the basilar membrane.
There is a corti organ on the basilar membrane. The corti organ is located on the scale media face of the basilar membrane. It is a receptor organ consisting of hair and support cells.
Hairy cells are divided into inner hair cells and outer hair cells. While 80% of the hairy cells around 16000 are made of outer hair cells, the rest is made up of inner hair cells.