Summary
The auditory organ in young Caimans (50 to 80 cms length) was studied with SEM and TEM. The auditory organ contains the basilar membrane with the papilla basilaris and the 3 internal ear cavities. A “fourth cavity” bordering on the scala tympani extends into the medial fibrocartilaginous plate. It contains the first nodal region of the myelinated afferent nerve fibres. The efferent nerve fibres occurring in this portion are not myelinated. The sensory cells may be divided into the inner and outer hair cells. The inner hair cells are medially positioned on the basilar membrane above the “fourth cavity”. They are of a high prismatic shape and have relatively long stereocilia. The quantity of the inner hair cells increases from the region near the window towards the lagena. The outer hair cells are calotte shaped and, for this reason, have a relatively large free surface. For the most part, they lie on the tympanic portion of the basilar membrane. The stereocilia of the outer hair cells are remarkably short in contrast to those of the inner hair cells. Seen as a whole, the length of the stereocilia of both types increases from the region near the window towards the lagena. The afferent and efferent innervation of the inner and outer hair cells is on principle the same. In contrast to the outer hair cells, the inner hair cells have more synapses with afferent axons. The efferent axons form axosomatic and axodendritic synapses. Within the region of the tympanic portion of the basilar membrane, the efferent axons also form synaptic contacts with the supporting cells and hyaline cells.
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References
Anderson, T. F.: Techniques for the preservation of three dimensional structure in preparing specimens for the electron microscope. Trans. N.Y. Acad. Sci. 13, 130–134 (1951)
Andres, K. H.: Zur methodischen Perfusionsfixierung des Zentralnervensystems von Säugern. Tg. Niederl. u. Dtsch. Gesellschaft f. Elektronenmikroskopie, Aachen (1965)
Andres, K. H.: Morphological criteria for the differentiation of synapses in vertebrates. J. Neurotrans. (in press) (1974)
Andres, K. H., Düring, M. v.: Interferenzphänomene am osmierten Präparat für die systematische elektronenmikroskopische Untersuchung. Mikroskopie (Wien) 30, 139–149 (1974)
Bagger-Sjöbäck, D., Wersäll, J.: The sensory hairs and tectorial membrane of the basilar papilla in the lizard calotes versicolor. J. Neurocytol. 2, 329–350 (1973)
Békésy, G. von: Experiments in hearing. New-York: McGraw-Hill 1960
Boord, R. L.: The efferent cochlear bundle in the Caiman and Pigeon. Exp. Neurol. 3 (3), 225–239 (1961)
Dohlmann, G. F.: Electron-microscopic examination of the inner ear of the pigeon. Acta oto-laryng. (Stockh.) 263, 3–7 (1970)
Düring, M. v.: The ultrastructure of lamellated mechanoreceptors in the skin of reptiles. Z. Anat. Entwickl.-Gesch. 143, 81–94 (1973)
Düring, M. v.: The ultrastructure of cutaneous receptors in the skin of Caiman crocodilus. Vortrag beim Symposium Mechanoreception SFB Bionach, 14.–18. 10. 73, Bochum—in press
Frishkopf, L. S., Flock, Å.: Ultrastructure of the basilar papilla, an auditory organ in the bullfrog. Acta oto-laryng. (Stockh.) 77, 176–184 (1974)
Gleisner, L., Flock, Å., Wersäll, J.: The ultrastructure of the afferent synapse on hair cells in the frog labyrinth. Act oto-laryng. (Stockh.) 76, 199–207 (1973)
Hamilton, D. W.: The inner ear of lizards.—I. Gross structure. J. Morph. 115, 255–271 (1964)
Hamilton, D. W.: The cilium on mammalian vestibular hair cells. Anat. Rec. 164, 253–258 (1969)
Held, H.: Die Cochlea der Säuger und der Vögel, ihre Entwicklung und ihr Bau. In: Handbuch der normalen und pathologischen Physiologie. XI. Receptionsorgane I, S. 467–534. Berlin: Julius Springer 1926
Jahnke, V., Lundquist, P. G., Wersäll, J.: Some morphological aspects of sound perception in birds. Acta oto-laryng. (Stockh.) 67, 583–601 (1969)
Kauffmann, G.: Zur Abhängigkeit der Cochlearpotentiale des Kaimans vom Stoffwechsel, von aktiven Transporten und von der Temperatur. J. comp. Physiol. 90, 245–273 (1974)
Kauffmann, G., Schwartzkopff, J.: On the dependence on metabolism of cochlear potentials in Caiman (Caiman crocodilus). Z. vergl. Physiol. 75, 105–107 (1971)
Miller, M. R.: The cochlear duct of lizards. Proc. Calif. Acad. Sci. 33, 255–259 (1966)
Miller, M. R.: Scanning electron microscope studies of some lizard basilar papillae. Amer. J. Anat. 138, 301–330 (1973)
Miller, M. R.: A scanning electron microscope study of the papilla basilaris of Gekko gecko. Z. Zellforsch. 136, 307–328 (1973)
Miller, M. R., Kasahara, M., Mulroy, M.: Observations on the structure of the cochlear duct limbus of reptiles. Proc. Calif. Acad. Sci. 35, No. 3, 37–52 (1967)
Mullinger, A. M., Smith, J. J. B.: Some aspects of the gross and fine structure of the amphibian papilla in the labyrinth in the Newt, Triturus cristatus. Tissue and Cell 1 (3), 403–416 (1969)
Necker, R.: Mikrophon- und Summationspotentiale des Vogelohrs bei N2-Beatmung. Naturwissenschaften 56, 143–144 (1969)
Necker, R.: Zur Entstehung der Cochlearpotentiale von Vögeln: Verhalten bei O2-Mangel, Cyanidvergiftung und Unterkühlung sowie Beobachtungen über die räumliche Verteilung. Z. vergl. Physiol. 69, 367–425 (1970)
Retzius, G.: Das Gehörorgan der Wirbeltiere. II. Das Gehörorgan der Reptilien, der Vögel und der Säugethiere, 368 pp., 39 pl. Stockholm: Samson & Wallin (1884)
Rosenhall, U.: Morphological patterns of the organ of Corti in birds. Arch. klin. exp. Ohr.-, Nas.-u. Kehlk.-Heilk. 22, 42–63 (1971)
Spöndlin, H.: The organization of the cochlear receptor. Fortschr. Hals-Nas.-Ohren-Heilk. 13, 26–37 (1966)
Spöndlin, H.: Innervationsprinzipien der Cochlea. In: Funktion und Therapie des Innenohres. III. Internationales Symposion in Halle (Saale) herausgegeben von H. Jakobi und P. Lotz, Johann Ambrosius Barth, Leipzig, S. 19–36 (1973)
Takasaka, T., Smith, C. A.: The structure and innervation pattern of the pigeon's basilar papilla. J. Ultrastruct. Res. 35, 20–65 (1971)
Tonndorf, J.: The transfer of energy across the cochlea. Acta oto-laryng. (Stockh.) 50, 177 (1959)
Wever, E. G.: Structure and function of the lizard ear. Aud. Res. 5, 331–371 (1965)
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Research supported by the DFG, SP Rezeptorphysiologie and SFB 114.
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von Düring, M., Karduck, A. & Richter, HG. The fine structure of the inner ear in caiman crocodilus. Z. Anat. Entwickl. Gesch. 145, 41–65 (1974). https://doi.org/10.1007/BF00519125
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DOI: https://doi.org/10.1007/BF00519125