|
|
Line 1: |
Line 1: |
| {{Header}}
| | #REDIRECT [[Paper - The genesis and structure of the membrana tectoria and the crista spiralis of the cochlea (1918)]] |
| {{Ref-Stricht1919}}
| |
| {| class="wikitable mw-collapsible mw-collapsed"
| |
| ! Online Editor
| |
| |-
| |
| | [[File:Mark_Hill.jpg|90px|left]] This 1919 historic paper by Van der Stricht describes the developing inner ear. Published in the series [[Book_-_Contributions_to_Embryology|Contributions to Embryology]] (Carnegie Institution of Washington).
| |
| <br>
| |
| See also by this author: {{Ref-Stricht1918}}
| |
| | |
| <br>
| |
| '''Modern Notes:'''
| |
| <br>
| |
| {{Hearing Links}}
| |
| | |
| |}
| |
| {{Historic Disclaimer}}
| |
| =The Arrangement And Structure Of Sustentacular Cells And Hair-Cells In The Developing Organ Of Corti=
| |
| | |
| By 0. Van der Stricht,
| |
| | |
| Professor of Histology and Embryology, Universily of Ghent,
| |
| Lecturer in Anatomy, Johns Hopkins University.
| |
| | |
| | |
| With four plates.
| |
| | |
| :'''Links:''' [[Book_-_Contributions_to_Embryology|Carnegie Institution of Washington - Contributions to Embryology]]
| |
| | |
| | |
| | |
| -----Content to be added----
| |
| | |
| | |
| {{Template:Historic Disclaimer}}
| |
| | |
| ==Introduction==
| |
| | |
| | |
| The arrangement of the outer sustentacular and hair-cells of the organ of
| |
| Corti in adult mammals is rather well known. According to the investigations
| |
| of Held (1902), N. Van der Stricht (1908), and Kolmer (1909), the body of the cell of
| |
| Deiters is situated below that of its sensory element, so that the two are connected
| |
| by a chalice-shaped, greatly modified segment, in the concavity of which hes the
| |
| deep cytoplasmic portion of the supported hair-cell. In the embrj'onic stages,
| |
| however, the relation between these two elements is entirely different, and it might
| |
| be well worth while to trace accurately their connections through the whole developmental stage. The same holds good for the inner and outer rods of Corti, the
| |
| inner supporting cells, and even some of the so-called cells of Hensen.
| |
| | |
| | |
| Most investigators who have tried to clarify the arrangement of the sensory
| |
| and sustentacular elements in embryonic material have made use of and describe
| |
| vertical radial sections of the organ of Corti. Although very interesting, and in fact
| |
| highly necessarj^, such preparations are hable to be deceptive and lead to misinterpretation. Indeed, most authors incorrectly represent the cells of Deiters. Many
| |
| authors, even Retzius (1884) and Held (1909), who describe the phalanx process of
| |
| the sustentacular elements as running obliquely from the cell body towards the
| |
| lamina reticularis, thus crossing two or three hair cells, generally picture it in illustrations of vertical radial sections as an uninterrupted band connecting the nucle-
| |
| ated portion of the cell with the free surface of the epitheUum. So, also, do most
| |
| authors of text-books of histology, notwithstancUng the fact that in a radial vertical
| |
| section this protoplasmic strand shows at least three interruptions.
| |
| | |
| By making use of sections tangential and alwaj^s somewhat obUque to the surface of the organ of Corti, N. Van der Stricht was able to accuratelj' locate the
| |
| nucleated body of the supporting elements in successive stages of development and
| |
| to determine the amount of gradual shifting. In this stud}' the same method of
| |
| research was apphed in order to locate the more superficial portions of these cells
| |
| between the sense-epitheUum elements, and to ascertain their exact relation to the
| |
| hair-cells and the mechanical factors that cause the shifting of the sustentacular
| |
| elements. Moreover, a series of preparations, exhibiting mitochondrial structures
| |
| in the supporting cells and hair-cells, has rendered it possible to define the nature of
| |
| coarser structures noted by previous observers.
| |
| | |
| | |
| ==Methods==
| |
| | |
| Kittens, dogs, and rabbits, from birth to 12 days old, white rat fetuses, and
| |
| young white rats about 2 days old, constituted the material used in these investigations. The isolatetl cochlea was fixed by trichloracetic acid (5 per cent in water),
| |
| by Bouin's or by Zenker's fluid, and subjected for many weeks to the mordant action
| |
| of some drops of iodine in alcohol (70 per cent). Where necessary, after fixation by
| |
| Bouin's or by Zenker's fluid, decalcification was completed by 2 per cent nitric acid
| |
| in 70 per cent alcohol. Before embedding in paraffin the pieces were stained with
| |
| borax carmine and the sections with iron hematoxylin, Congo red, and light green.
| |
| | |
| The mitochondria in the sustentacular and hair-cells were fixed in the following
| |
| manner: Mixture of formalin and bichromate of Regaud (1910), according to the
| |
| modifications indicated by Cowdry (1916), and subsequent staining with acid
| |
| fuchsin and methjd-green ; treatment by a 1 per cent aqueous solution of osmic acid
| |
| for about an hour, followed by immersion in trichloracetic acid, or Bouin's or
| |
| Zenker's fluid; exposure of the cochlea, the bony wall of which had been previously
| |
| provided with two or three small o[)enings, to vapors from a 2 per cent a([ueous
| |
| solution of osmic acid for approximately 30 to 60 minutes, and subsequent treatment of the piece by one of the three above-mentioned agents; fixation for an hour
| |
| in a 1 per cent aqueous solution of osmic acid, followed bj' immersion in a 1 per cent
| |
| aqueous solution of silver nitrate for 3 hours. By these methods of fixation, and
| |
| staining with iron hematoxylin and Congo red, the mitochondria can be brought
| |
| into prominence within one or two turns of the cochlea, occasionally throughout its
| |
| extent. Osmic vajjors have been recommended as a fixing agent for mitochondrial
| |
| structures by M. R. Ijcwis and W. H. Lewis (1914). We are able to confirm tins
| |
| statement, having for many years successfully used these vapors, and a subsequent
| |
| treatment by another reagent, for the purpose of fixing the chondriomites in the
| |
| ova of the dog. Henneguy (1895) was able to bring into view chondrioconts in the
| |
| spermatocytes of Helix by the use of osmic vapors.
| |
| | |
| The description given herein is illustrated by figures representing three different
| |
| series of sections:
| |
| | |
| (1) Radial, vertical sections of tho organ of Corti. These are cross-sections of the
| |
| rows of hair and supporting colls, the knife cutting the latter along their length and from
| |
| the axis toward the outer wall of the cochlea (figs. 14, 15, and 16).
| |
| | |
| (2) Spiral, vertical sections of the organ of Corti, these being longitudinal sections of
| |
| the parallel spiral rows, the knife cutting the hair and supporting cells along their length,
| |
| from the more apical to the more liasal part of the sjiiral organ (figs. 19, 20, 22, and 23).
| |
| | |
| (3) Sections tangential and always somewhat oblique to the surface of the organ of
| |
| Corti, the knife cutting transversely the hair and sustentacular cells of the spiral parallel
| |
| rows at all levels, from the surface of the epithehum towards the basilar membrane (figs.
| |
| 2 tf) 13, 17 and 18), so that their arrangement and structure can be traced in cross-sections
| |
| throughout their lengths (figs. 2 and 3).
| |
| | |
| | |
| :'''Links:''' [[Book_-_Contributions_to_Embryology|Carnegie Institution of Washington - Contributions to Embryology]]
| |
| | |
| | |
| | |
| -----Content to be added----
| |
| | |
| | |
| {{Template:Historic Disclaimer}}
| |
| | |
| | |
| {{Glossary}}
| |
| | |
| {{Footer}}
| |
| | |
| [[Category:Historic Embryology]] [[Category:Human]]
| |