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Section through the cochlea (schematic)
  • Perilymph of the Scala vestibuli and Scala tympani (both are connected via the Helicotrema)
  • Endolymph of the scala media
  • The endolymph ( ancient Greek ἔνδον endon , German 'inside' and Latin lympha 'clear water' ) is necessary for the function of the hearing organ and the organ of equilibrium .

    The endolymph is a potassium-rich fluid that is similar to intracellular fluid. It is formed in specialized areas ( stria vascularis ) by the epithelium of the labyrinth, probably from the perilymph . In humans, the endolymph space only holds about 70 µl per side. He is above the Endolymphgang ( endolymphatic duct ) with the Endolymphsack ( endolymphatic sac ) in conjunction. In humans, the endolymph sac, which lies between two dural sheets , is located on the dorsal surface of the bony temporal bone pyramid ( Pars petrosa ossis temporalis ) in a shallow pit ( Apertura canaliculi vestibuli ). This sack serves to regulate the volume in the membranous labyrinth.

    Due to the different composition of the endolymph and in the adjacent cavities atrial staircase ( scala vestibuli ) and scala tympani ( scala tympani ) of the cochlea located perilymph there is an electrical voltage difference between screw flight (scala media or cochlear duct ) and scala vestibuli and scala tympani. This voltage difference supplies the energy for the conversion of the sound waves into nerve impulses in the organ of Corti .

    Movements of the endolymph within the semicircular canals and the macular organs of the equilibrium organ are triggered by movements of the head or the body as a whole. These fluid shifts trigger a displacement of the cilia of the equilibrium receptors ( ampullae membranaceae , macula sacculi and macula utriculi ).

    See also


    • Uwe Gille: Ear, Auris . In: Franz-Viktor Salomon, Hans Geyer, Uwe Gille (Ed.): Anatomy for veterinary medicine . 2nd expanded edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , pp. 612-621 .

    Individual evidence

    1. Joachim Kirsch, Christian Albrecht May, Dietrich Lorke: Pocket textbook anatomy . Georg Thieme Verlag, 2010, ISBN 978-3-13-162511-3 , p. 689 .