5 hafta sonra oluşan ve ses dalgalarını algıladıktan sonra bir çeşit sinirsel sinyale
dönüştürerek beyne göndermeye yarayan kulağımızın en önemli bölümüdür.
The bony capsule has been dissected out, showing the 2 1/2 coils of the membranous labyrinth (35 mm in
length). The oval (o) and round (r) windows are indicated. Bar: 0.5mm
Cross section of the whole cochlea.
This mid-modiolar section shows the coiling of
the cochlear duct
(1) containing endolymph and the scala vestibuli
(3) containing perilymph. The red arrow is from the oval window, the blue arrow points to the round
window. Within the modiolus,
yellow indicates the spiral ganglion
(4) and auditory nerve fibers
(5). For details, see the single turn cross section below.
The cochlear duct (3) is isolated from the scala vestibuli (1) and
scala tympani (2) by the Reissner's (10) and basilar (5) membranes
respectively. The organ of Corti is covered by the tectorial membrane (6) floating in the
The stria vascularis (8) and the fibres (7) going to the spiral ganglion are also
SEM view of a rat cochlear spiral (the bony capsule, stria and tectorial membrane have been
In rat, the basilar membrane develops a 3 turn spiral of a total length of 22 mm
(compare with the coiling in human). Only the extreme base (hook) is not
Yellow boxes link to higher magnification pictures showing the hair cell surfaces and stereocilia
at both base and apex.
Distribution of frequencies (passive tonotopy) along the basilar membrane according to G. von
Lines of preferential frequency vibrations (kHz) are indicated in blue on the
diagram. Note, from base (20 kHz) to
apex (50 Hz), a gradual enlargement of the basilar membrane. See also an uncoiled
representation and superimposed traveling waves.