Allgemeine Pathologie und pathologische Anatomie

Krause, F.; Merkel,; Zipper,; Schott, Adolf; Merkel, H.; Bode,; Bauer, K. H.; Köhler, Hans; Haagen,

doi:10.1007/bf01756144

Cited by 1 publication

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“…In determining the size of the hair-cell population, Retzius (3) used a method that had been developed earlier by Wal-deyer (4) and Krause (5) in the study of inner ear anatomy, and had been applied by them in working out the numbers of hair cells in the human cochlea. The method was based upon a surgical approach consisting of a careful dissection away of the bony cochlear walls to expose progressively the delicate structures within, and allow a direct examination of these structures under suitable magnification.…”

Section: The Hair Cellsmentioning

confidence: 99%

The Cochlea of the Dolphin, Tursiops truncatus: Hair Cells and Ganglion Cells

Wever

McCormick

Palin

et al. 1971

Proc. Natl. Acad. Sci. U.S.A.

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A study of the cochlear hair cells in Tursiops truncatus showed 3451 inner and 13,933 outer hair cells, for a total of 17,384. This total is of the same order of magnitude as the value of 14,975 for the human ear. Determination of the ganglion cell population for the dolphin gave a total of 95,004 cells, which is about three times as many as in man.The large number of hair cells in the dolphin ear suggests a high order of auditory proficiency in general, and especially a marked ability of tonal differentiation. The large ratio of ganglion cells to hair cells suggests unusual capabilities in the utilization of auditory information.In two previous reports (1, 2), we described the general morphology of the dolphin cochlea and gave particular consideration to the form of the basilar membrane and its manner of suspension. This paper deals with the numbers of hair cells and ganglion cells and their distribution along the cochlea. These features are of interest because they relate to questions of the specificity with which the action of sounds on the ear can be represented at the level of hair-cell stimulation and in the initial involvement of the auditory nervous system. THE HAIR CELLSEarly in the study of the anatomy of the vertebrate ear, it was observed that as we go from simpler to more advanced forms, we find a large increase in the size of the auditory papilla and in the numbers of its hair cells. Among the mammals, Retzius in 1884 found this increase in numbers in the series from the rabbit through the cat to man. It was readily inferred that this progression is related to the characteristics of these different ears in tonal range and frequency discrimination.In determining the size of the hair-cell population, Retzius (3) used a method that had been developed earlier by Waldeyer (4) before the development of serial sectioning. It requires much patience and skill, but provides an excellent orientation and appreciation of the forms of anatomical elements.Waldeyer in 1872 examined the human cochlea by this procedure; his work was followed by that of Krause in 1876. These investigators exposed the organ of Corti in one region of the cochlea and counted the outer pillar cells over some convenient distance, from which they obtained the average spacing of these elements. They assumed that the hair cells (that were much more difficult to see under their conditions) had the same spacing as the outer pillar cells. Then, they measured the length of the auditory papilla (or the basilar membrane); by dividing this length by the spacing, they obtained an estimate of the number of elements in a row along the cochlea. Finally, by multiplying this figure by the number of rows, they found the total number of hair cells.Retzius repeated these measurements with some refinements of technique and with the observation that in man there are only three rows of outer hair cells over most of the cochlea, whereas his predecessors had thought that there were four rows throughout. Retzius found four rows only in the apical region...

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Section: The Hair Cellsmentioning

confidence: 99%