膜様半規管壁細胞の光学顕微鏡的観察

A STUDY ON THE CELL STRUCTURES OF THE WALL OF THE MEMBRANOUS SEMICIRCULAR CANAL BY MEANS OF LIGHT MICROSCOPE

　I．はじめに

　前庭迷路系に対して回転刺激を加えた場合に，膜様半規管内の内リンパ流動が起こり（Mach-Breuer），それによつてクプラが変位し感覚細胞を興奮させると考えられている^1）。

　外側，前および後半規管の各々に同じ強さの回転刺激が加えられた際に，それぞれにおいて，同じ大きさの刺激として感覚細胞に達するか否かの最初の関門が膜様半規管の形態と，その壁細胞の構築によると考えられる。

　Retziusが1884年に内耳の解剖を発表している^2）。その中に半規管壁細胞についても記載があるが，詳細については十分でない。そこで膜様半規管壁の細胞構築の上で，各半規管における差が認められるか否かを観察した。

　Observations through means of optical microscope were made on the cells that compose the wall the membranous semicircular canal both, in the guinea pig and that of the human being. Between the cells of the guinea pig and that of the human being a certain morphological difference is recognized. However, the number of cells composing the cross section of the canal at a given point showed no difference. Yet, there might be a possibility of a functional difference to be existing between the circulation of the endolymph in the two.

　In the human being there is no difference in the three semicircular canals in their cell number and morphology and they are provided with subepithelial structures. A layer of collagen provided with blood vascular network lies between the epithelial and subepithelial structures. By such evidence alone, it is not concieveable to consider the functional difference existing in the three semicircular canals. However, the ciliated cells might hold the key to the situation in which the difference may be caused by hindrance in the circulation of the endolymph in the respective canals.