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→Inner Ear
*The membranous labyrinth is an interconnected group of fluid-filled membranous sacs. The fluid is endolymph.
*The membranous labyrinth is an interconnected group of fluid-filled membranous sacs. The fluid is endolymph.
*It is the movement of the endolymph that stimulates the sensory cells within the membranous wall.
*It is the movement of the endolymph that stimulates the sensory cells within the membranous wall.
*The membranous labyrinth consists of:
*The membranous labyrinth consists of:
- ''Ductus reuniens'': this is the duct through which the above two labyrinths communicate
- ''Ductus reuniens'': this is the duct through which the above two labyrinths communicate
*The bony labyrinth consists of:
*The bony labyrinth consists of:
- ''Vestibule'': a chamber in the centre of the bony labyrinth, which communicates with both the cochlea and the semicircular canals. The oval and the round windows are both located in the lateral wall of the vestibule.
- ''Vestibule'': a chamber in the centre of the bony labyrinth, which communicates with both the cochlea and the semicircular canals. The oval and the round windows are both located in the lateral wall of the vestibule.
- ''Semicircular canals'': contain the semicircular ducts, which have arised from the utricle of the vestibular labyrinth. There are three semicircular canals, corresponding to the three dimensions in which you can move, so they are almost at right angles with each other. Each duct has two crura (leg-like parts). One crus of each duct has an ampulla, which is an expansion of the duct. Movement of endolymph stimulates receptor cells within the ampullae.
- ''Semicircular canals'': contain the semicircular ducts, which have arisen from the utricle of the vestibular labyrinth. There are three semicircular canals, corresponding to the three dimensions in which you can move, so they are almost at right angles with each other. Each duct has two crura (leg-like parts). One crus of each duct has an ampulla, which is an expansion of the duct. Movement of endolymph stimulates receptor cells within the ampullae.
- ''Cochlea'': forms a spiral around a central hollow core of bone, called the modiolus,which contains the cochlear nerve. The spiral lamina projects into the spiral canal, partially bisecting the lumen into two parts, which are called the scala tympani and the scala vestibuli. The scala media (the cochlear duct) is inbetween these two parts.
- ''Cochlea'': forms a spiral around a central hollow core of bone, called the modiolus,which contains the cochlear nerve. The spiral lamina projects into the spiral canal, partially bisecting the lumen into two parts, which are called the scala tympani and the scala vestibuli. The scala media (the cochlear duct) is inbetween these two parts.