Membranous labyrinth (English)

The membranous labyrinth is suspended within the perilymph of the bony labyrinth thus mirroring its overall structure. The central part of the membranous labyrinth is located within the bony vestibule. It consists of two sacs: utricle and saccule, which communicate via a small duct called the ductus reuniens. The utricle lies in the posterior part of the vestibule, while the saccule lies anteriorly. The three membranous semicircular ducts branch from the utricle and pass through the semicircular canals. Similar to their bony counterparts, the canals originate with membranous ampullae (anterior, posterior, lateral). The anterior and posterior duct unite as well, forming the common membranous limb.The bony cochlea houses the membranous cochlear duct which follows its spiral course. The whole membranous labyrinth is filled with endolymph. Movement of endolymph stimulates the receptor cells within the walls of the labyrinth, producing neuronal stimuli related to balance and hearing. These stimuli are conveyed via the vestibulocochlear nerve, whose components can be seen innervating different parts of the labyrinth. Essentially, the vestibular nerve innervates the utricle, saccule and semicircular ducts, via its branches, conveying the information about balance. Branches of the cochlear nerve innervate the spiral organ of Corti that is located in the cochlea, providing information about hearing.