Microstructures of the Osseous Spiral Laminae in the Bat Cochlea: A Scanning Electron Microscopic Study.
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- KÜCÜK Babür
- Department of Anatomy, Hokkaido University School of Medicine
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- 阿部 和厚
- 北海道大学医学部解剖学第三講座
抄録
The architecture and surface structures of the primary and secondary osseous spiral laminae in the cochlea of the bat, an animal able to hear high frequency sounds, were examined by scanning electron microscopy to understand the micromechanical adaptations of the bony supportive elements in the inner ear to the specific hearing function. The bat used was Myotis frater kaguyae.<br>The myotis bat cochlea was seen to consist of a hook and a spiral portion with one and three-quarter turns and was characterized by: 1) a distinct ridge-like projection running spirally along the middle line on the vestibular leaf of the primary osseous spiral lamina; 2) a wide secondary osseous spiral lamina; and 3) a narrow spiral fissure between the primary and secondary osseous spiral laminae. The ridge on the primary osseous spiral lamina was 150μm high in the hook and basal turn, then lowered toward apex, and flattened before the apical end. The surface structures appeared to provide a firm anchorage of the auditory teeth. The secondary osseous spiral lamina, which anchors the fibers of the basilar membrane, was sharply projected and measured 150μm in width in the hook, and then narrowed gradually toward apex to disappear in the helicotrema. The spiral fissure for the basilar membrane was about 40μm in width in the hook and about 120μm in the apical turn.<br>The findings suggest the presence of a narrow and rigid basilar membrane with a high amount of fibers and a strong bony support to the auditory teeth for scaffolding the tectorial membrane during intense vibration in response to high frequency sounds. The above-mentioned specialized structures of the primary and secondary osseous spiral laminae in the bat cochlea appear to adapt to the micromechanics of high frequency hearing functions.
収録刊行物
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- Ａｒｃｈｉｖｅｓ ｏｆ Ｈｉｓｔｏｌｏｇｙ ａｎｄ Ｃｙｔｏｌｏｇｙ
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Ａｒｃｈｉｖｅｓ ｏｆ Ｈｉｓｔｏｌｏｇｙ ａｎｄ Ｃｙｔｏｌｏｇｙ 55 (3), 315-319, 1992
国際組織細胞学会