Literaturdatenbank
Literaturdatenbank |
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Bellin, D. A. (2000). Scanning electron microscopy of the turtle saccule. Dissertation, San Jose State University.
Added by: Admin (14 Aug 2008 22:46:38 UTC) Last edited by: Sarina Wunderlich (11 Oct 2008 13:35:30 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Bellin2000a View all bibliographic details  |
Categories: General Keywords: Histologie = histology, Morphologie = morphology, Schildkröten = turtles + tortoises Creators: Bellin Publisher: San Jose State University |
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| Abstract |
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Little information is available concerning the structure of the reptilian saccular macula (Baird, In: Biology of the Reptilia, 1970; Jorgensen, Acta Zoologica 55:289-298, 1974; Sneary, ARO Abstracts 1996). This study extends the database to include information derived from SEM micrographs. The turtle saccule is filled with a membrane-bound otoconial mass and is lined by a simple epithelium. The macular epithelium is situated along the margin of this large space. The main population of hair cells extends anteriorly and dorsally in a long, curved arm that is covered by an extension of the otoconial mass. As previously reported, bundles are generally polarized away from the midline of the epithelium. Three regions may be identified with respect to bundle morphology. The central striolar region has approximately 10 cells across its short axis and extends into the arm with no reduction in width. Hair cell bundles in the striola have approximately 50 stereovilli in staggered arrays. A steep slope is created by the significant increase in height from the shortest to the tallest members. Each bundle is rectangular in shape and displays an unbulbed kinocilium that does not extend above the tallest stereovilli. Moreover, in prepared specimens the striolar region displays very little otoconial membrane debris. In the arm, extrastriolar regions are narrower in width, so that the epithelium is approximately one-half the total width of the main population. Here, bundles close to the striola have a distinct and intermediate morphology. They are significantly shorter, often one-half as tall as in the striola, and have stereovilli that are arranged in straight rows. In addition, these bundles have a more triangular shape than those in the striola. Close to the edge of the macula, in the peripheral striolar regions, bundles have even fewer stereovilli and are even shorter. In addition, the kinocilium is more than double the length of the tallest stereovilli and is tipped with a prominent bulb. The periphery of the macula is always covered with significant otoconial membrane debris, often obscuring the bundles.Supported by NIH (MBRS) grant GM 08192-19
Added by: Sarina Wunderlich |