Overview: Membranous labyrinth

The utricle of the membranous labyrinth is a large chamber housed within the vestibule of the osseous labyrinth. The receptor it contains, the macula, responds to stimuli of linear acceleration and gravitational forces. The utricle connects with the saccule via a small duct and with the semicircular ducts.

The saccule of the membranous labyrinth is a smaller chamber housed within the vestibule of the osseous labyrinth. The receptor it contains, the macula, also responds to stimuli of linear acceleration and gravitational forces. The saccule is connected by small ducts to the utricle and to the cochlear duct.

The semicircular ducts of the membranous labyrinth are three tubes housed within the semicircular canals of the osseous labyrinth. Each duct contains a receptor, a crista ampullaris, that responds to angular acceleration. Each crista is located within an enlargement, the ampulla, situated adjacent to the utricle. The semicircular ducts connect with the utricle.

The semicircular ducts of the membranous labyrinth are three tubes housed within the semicircular canals of the osseous labyrinth. Each duct contains a receptor, a crista ampullaris, that responds to angular acceleration. Each crista is located within an enlargement, the ampulla, situated adjacent to the utricle. The semicircular ducts connect with the utricle.

The cochlear duct, spiraling through the center of the cochlea of the osseous labyrinth, communicates through a small duct with the saccule. The receptor in the cochlear duct, the organ of Corti, responds to sound vibrations.

The endolymphatic duct, formed by the union of two small ducts from the utricle and saccule, extends toward the brain, where it terminates as an enlargement, the endolymphatic sac, between layers of the meninges. The endolymphatic duct probably functions to absorb endolymph.