The Cochlea

  • Leonard P. Rybak


The mammalian cochlea is an intricately designed organ that is exquisitely sensitive to sound. It possesses unique physical and chemical properties that permit this organ to function properly. This chapter describes some of the features of the cochlea including the cells that line the fluid filled spaces of the cochlear duct and the chemical composition of the fluids that allow the tissues to produce resting and acting potentials that assist in the transduction of acoustic stimuli into electrical signals to the brain. The structure of key structures in the cochlea are illustrated with light microscopy and ultrastructural images, including transmission and scanning electron microscopy. The unusual structural and functional features of these cells allow them to function in an orderly and precise fashion to shape the special sensory function of hearing in the normal cochlea of mammals.


Cochlea Stria vascularis Hair cells Spiral ligament Spiral ganglion neurons Organ of corti Transduction Tectorial membrane Basilar membrane Perilymph Endolymph 



Dr. Rybak was supported by NIH grant DC02396 from NIDCD.


  1. Adachi N, Yoshida T, Nin F, Ogata G, Yamaguchi S, Suzuki T, Komune S, Hisa Y, Hibino H, Kurachi Y. The mechanism underlying maintenance of the endocochlear potential by the K+ transport system in fibrocytes of the inner ear. J Physiol. 2013;591:4459–72.CrossRefPubMedPubMedCentralGoogle Scholar
  2. Andrade LR, Salles FT, Grati M, Manor U, Kachar B. Tectorins crosslink type II collagen fibrils and connect the tectorial membrane to the spiral limbus. J Struct Biol. 2016;194:139–46.CrossRefPubMedPubMedCentralGoogle Scholar
  3. Ben Said M, Grati M, Ishimoto T, Zou B, Chakchouk I, Ma Q, Yao Q, Hammami B, Yan D, Mittal R, Nakamichi N, Ghorbel A, Neng L, Tekin M, Shi XR, Kato Y, Masmoudi S, Lu Z, Hmani M, Liu XL. A mutation in SLC22A4 encoding an organic cation transporter expressed in the cochlea strial endothelium causes human recessive non-syndromic hearing loss DFNB60. Hum Genet. 2016;135:513–24.CrossRefPubMedPubMedCentralGoogle Scholar
  4. Bohne BA, Harding GW. Cochlear anatomy. In: Clark WW, Ohlemiller KK, editors. Anatomy and physiology of hearing for audiologists. Clifton Park: Thomson Delmar Learning; 2008. p. 109–22.Google Scholar
  5. Cazals Y, Bevengut M, Zanella S, Brocard F, Barhanin J, Gestreau C. KCNK5 channels mostly expressed in cochlear outer sulcus cells are indispensable for hearing. Nat Commun. 2015;6:8780.CrossRefPubMedPubMedCentralGoogle Scholar
  6. Chang Q, Wang J, Li Q, Kim Y, Zhou B, Wang Y, Li H, Lin X. Virally mediated Kcnq1 gene replacement therapy in the immature scala media restores hearing in a mouse model of human Jervell and Lange-Nielsen deafness syndrome. EMBO Mol Med. 2015;7:1077–86.CrossRefPubMedPubMedCentralGoogle Scholar
  7. Chiarella G, Petrolo C, Cassandro E. The genetics of Meniere’s disease. Appl Clin Genet. 2015;8:9–17.CrossRefPubMedPubMedCentralGoogle Scholar
  8. Dallos P, Wu X, Cheatham MA, Gao J, Zheng J, Anderson CT, Jia S, Wang X, Cheng WH, Sengupta S, He DZ, Zuo J. Prestin-based outer hair cell motility is necessary for mammalian cochlear amplification. Neuron. 2008;58:333–9.CrossRefPubMedPubMedCentralGoogle Scholar
  9. Fettiplace R. Is TMC1 the hair cell mechanotransducer channel? Biophys J. 2016;111:3–9.CrossRefPubMedPubMedCentralGoogle Scholar
  10. Fettiplace R. Hair cell transduction, tuning and synaptic transmission in the mammalian cochlea. Compr Physiol. 2017;7:1197–227.CrossRefPubMedPubMedCentralGoogle Scholar
  11. Fettiplace R, Hackney CM. The sensory and motor roles of auditory hair cells. Nat Neurosci. 2006;7:19–29.CrossRefGoogle Scholar
  12. Forge A, Becker D, Casalotti S, Edwards J, Evans WH, Lench N, Souter M. Gap junctions and connexin expression in the inner ear. Novartis Found Symp. 1999;219:134–50.PubMedGoogle Scholar
  13. Fuchs PA, Glowatzki E, Moser T. The afferent synapse of cochlear hair cells. Curr Opin Neurobiol. 2003;13:452–8.CrossRefPubMedGoogle Scholar
  14. Giese APJ, Tang Y-Q, Sinha GP, Bowl MR, Goldring AC, Parker A, Freeman MJ, Brown SDM, Riazuddin S, Fettiplace R, Schafer WR, Frolenkov GI, Ahmed Z. CiB2 interacts with TMC1 and TMC2 and is essential for mechanotransduction in auditory hair cells. Nat Commun. 2017;8(1):43.CrossRefPubMedPubMedCentralGoogle Scholar
  15. Goutman JD, Elgoyhen AB, Gomez-Casati ME. Cochlear hair cells: the sound-sensing machines. FEBS Lett. 2015;589:3354–61.CrossRefPubMedPubMedCentralGoogle Scholar
  16. Gow A, Davies C, Southwood CM, Frolenkov G, Chrustowski M, Ng L, Yamauchi D, Marcus DC, Kachar B. Deafness in Claudin 11-null mice reveals the critical contribution of basal cell tight junctions to stria vascularis function. J Neurosci. 2004;24:7051–62.CrossRefPubMedPubMedCentralGoogle Scholar
  17. Hibino H, Nin F, Tsuzuki C, Kurachi Y. The specific architecture of the stria vascularis and the roles of the ion-transport apparatus. Pflugers Arch - Eur J Physiol. 2010;459:521–33.CrossRefGoogle Scholar
  18. Hudspeth AJ. How the ear’s works work. Nature. 1989;341:397–404.CrossRefPubMedGoogle Scholar
  19. Jagger DJ, Forge A. The enigmatic root cell—emerging roles contributing to fluid homeostasis within the cochlear outer sulcus. Hear Res. 2013;303:1–11.CrossRefPubMedGoogle Scholar
  20. Kim HJ, Gratton MA, Lee J-H, Perez Flores MC, Wang W, Doyle KJ, Beermann F, Crognale MA, Yamoah EN. Precise toxigenic ablation of intermediate cells abolishes the “battery” of the cochlear duct. J Neurosci. 2013;33:14601–6.CrossRefPubMedPubMedCentralGoogle Scholar
  21. Kubisch C, Schroeder BC, Friedrich T, Leutjohann B, El-Amraoui A, Marlin S, Petit C, Jentsch TJ. KCNQ4, a novel potassium channel expressed in sensory outer hair cells, is mutated in dominant deafness. Cell. 1999;96:437–46.CrossRefPubMedGoogle Scholar
  22. Lang F, Vallon V, Knipper M, Wangemann P. Functional significance of channels and transporters expressed in the inner ear and kidney. Am J Physiol Cell Physiol. 2007;293:C1187–208.CrossRefPubMedGoogle Scholar
  23. Liu H, Li Y, Chen L, Zhang Q, Pan N, Nichols DH, Zhang WJ, Fritsch B, He DZZ. Organ of Corti and stria vascularis: is there an interdependence for Survival? PLoS One. 2016;11(12):w0168953. Scholar
  24. Liu W, Schrott-Fischer A, Glueckert R, Benav H, Rask-Andersen H. The human “cochlear battery” –claudin-11 barrier and ion transport proteins in the lateral wall of the cochlea. Front Mol Neurosci. 2017;10:239.
  25. Milewski AR, Maoileidigh DO, Salvi JD, Hudspeth AJ. Homeostatic enhancement of sensory transduction. Proc Natl Acad Sci U S A. 2017;114:E6794–803.CrossRefPubMedPubMedCentralGoogle Scholar
  26. Mittal R, Aranke M, Debs LH, Nguyen D, Patel AP, Grata M, Mittal J, Yan D, Chapagain P, Eshraghi AA, Liu XZ. Indispensable role of ion channels and transporters in the auditory system. J Cell Physiol. 2017;232:743–58.CrossRefPubMedGoogle Scholar
  27. Molina L, Fasquelle L, Nouvian R, Salvetat N, Scott HS, Guipponi M, Molina F, Puel JL, Delprat B. Tmprss3 loss of function impairs cochlear inner hair cell Kcnma1 channel membrane expression. Hum Mol Genet. 2013;22:1289–99.CrossRefPubMedGoogle Scholar
  28. Nam J-H, Fettiplace R. Optimal electrical properties of outer hair cells ensure cochlear amplification. PLoS One. 2012;7(11):e50572. Scholar
  29. Nin F, Yoshida T, Sawamura S, Ogata G, Ota T, Higuchi T, Murakami S, Doi K, Kurachi Y, Hibino H. The unique electrical properties in an extracellular fluid of the mammalian cochlea; their functional roles, homeostatic processes, and pathological significance. Pflugers Arch - Eur J Physiol. 2016;468:1637–49.CrossRefGoogle Scholar
  30. Raphael Y, Altschuler RA. Structure and innervation of the cochlea. Brain Res Bull. 2003;60:397–422.CrossRefGoogle Scholar
  31. Ren T, He W, Kemp D. Reticular lamina and basilar membrane vibrations in living mouse cochleae. Proc Natl Acad Sci U S A. 2016;113:9910–5.CrossRefPubMedPubMedCentralGoogle Scholar
  32. Schaechinger TJ, Gorbunov D, Halaszovich CR, Moser T, Kugler S, Fakler B, Oliver D. A synthetic prestin reveals prestin protein domains and molecular operation of outer hair cell piezoelectricity. EMBO J. 2011;30:2793–804.CrossRefPubMedPubMedCentralGoogle Scholar
  33. Semaan MT, Alagramam KN, Megerian CA. The basic science of Meniere’s disease and endolymphatic hydrops. Curr Opin Otolaryngol Head Neck Surg. 2005;13:301–7.CrossRefPubMedGoogle Scholar
  34. Shi X. Pathophysiology of the cochlear intrastrial fluid-blood barrier (review). Hear Res. 2016;338:52–63.CrossRefPubMedPubMedCentralGoogle Scholar
  35. Shodo R, Hayatsu M, Koga D, Horii A, Ushiki T. Three-dimensional reconstruction of root cells and interdental cells in the rat inner ear by serial section scanning electron microscopy. Biomed Res (Tokyo). 2017;38(4):239–48.CrossRefGoogle Scholar
  36. Spicer SS, Schulte BA. The fine structure of spiral ligament cells relates to ion return to the stria and varies with place-frequency. Hear Res. 1996; 100(1–2):80–100.CrossRefPubMedGoogle Scholar
  37. Steel KP, Barkway C. Another role for melanocytes: their importance for normal stria vascularis development in the mammalian inner ear. Development. 1989;107:453–63.PubMedGoogle Scholar
  38. Sterkers O, Ferrary E, Amiel C. Production of inner ear fluids. Physiol Rev. 1988;68:1083–128.CrossRefPubMedGoogle Scholar
  39. Stöver T, Diensthuber M. Molecular biology of hearing. GMS Curr Top Otorhinolaryngol Head Neck Surg. 2011;10:Doc06. Epub 2012 Apr 26.
  40. Verpy E, Leibovici M, Michalski N, Goodyear RJ, Houdon C, Weil D, Richardson GP, Petit C. Stereocilin connects outer hair cell stereocilia to one another and to the tectorial membrane. J Comp Neurol. 2011;519:194–210.CrossRefPubMedPubMedCentralGoogle Scholar
  41. Von Bekesy G. Resting potentials inside the cochlear partition of the guinea pig. Nature. 1952;169:241–2.CrossRefGoogle Scholar
  42. Wu Z, Grillet N, Zhao B, Cunningham C, Harkins-Perry S, Coste B, Ranade S, Zebarjadi N, Beurg M, Fettiplace R, Patapoutian A, Mueller U. Mechanosensory hair cells express two molecularly distinct mechanotransduction channels. Nat Neurosci. 2017;20:24–33.CrossRefPubMedGoogle Scholar
  43. Yang Y, Dai M, Wilson TM, Omelchenko I, Klimek JE, Wilmarth PA, David LL, Nuttall AL, Gillespie PG, Shi X. Na+/K+-ATPase α1 identified as an abundant protein in the blood-labyrinth barrier that plays an essential role in the barrier integrity. PLoS One. 2011;6(1):e16547. Scholar
  44. Yoo JC, Kim HY, Han KH, Oh SH, Chang SO, Marcus DC, Lee JH. Na+ absorption by Claudius’ cells is regulated by purinergic signaling in the cochlea. Acta Otolaryngol. 2012;132(Suppl 1):S103–8.CrossRefPubMedGoogle Scholar
  45. Yoshida T, Nin F, Murakami S, Ogata G, Uetsuka S, Choi S, Nakagawa T, Inohara H, Komune S, Kurachi Y, Hibino H. The unique ion permeability profile of cochlear fibrocytes and its contribution to establishing their positive resting membrane potential. Pflugers Arch. 2016;468:1609–19.CrossRefPubMedGoogle Scholar
  46. Zwaenepoel I, Mustapha M, Leibovici M, Verpy E, Goodyear R, Liu XZ, Nouaille S, Nance WE, Kanaan M, Avraham KB, Tekaia F, Loiselet J, Lathrop M, Richardson G, Petit C. Otoancorin, an inner ear protein restricted to the interface between the apical surface of sensory epithelia and their overlying acellular gels, is defective in autosomal recessive deafness DFNB22. Proc Natl Acad Sci U S A. 2002;99:6240–5.CrossRefPubMedPubMedCentralGoogle Scholar

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© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Division of Otolaryngology, Department of SurgerySouthern Illinois University, School of MedicineSpringfieldUSA

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