Braekevelt C R
Anat Anz. 1980;148(3):225-35.
The normal morphology of the retinal epithelium has been studied by transmission electron microscopy in the eye of a teleost; the scissortail (Rasbora trilineata). The retinal epithelium forms a single layer of cells joined laterally by cell junctions. Centrally in the retina these cells are columnar while moving peripherally they are cuboidal and eventually squamous in shape. Apical processes of these cells enclose photoreceptor inner and outer segments and reach almost to the external limiting membrane. Few basal infoldings are seen. In addition to the usual cell organelles seen in retinal epithelial cells, i. e., abundant smooth endoplasmic reticulum, numerous mitochondria and phagosomes, the central epithelial cells contain numerous lipid tapetal spheres and a few melanosomes. Peripherally the cells contain few or no tapetal spheres and more melanosomes. A population of wandering phagocytes within the epithelial layer is described. Bruch's membrane shows a three-layered composition rather than the usual pentalaminate structure seen in most vertebrates. The choriocapillaris endothelium facing Bruch's membrane is very thin but displays only a few fenestrae.
通过透射电子显微镜对一种硬骨鱼——剪刀尾（三线波鱼）的眼睛进行研究，观察了视网膜上皮的正常形态。视网膜上皮形成单层细胞，通过细胞连接在侧面相连。在视网膜中央，这些细胞呈柱状，向周边移动时变为立方状，最终呈鳞状。这些细胞的顶端突起包围着光感受器的内节和外节，几乎延伸到外界膜。可见少量基底褶。除了视网膜上皮细胞中常见的细胞器，即丰富的滑面内质网、大量线粒体和吞噬体之外，中央上皮细胞还含有大量脂质反光球体和少量黑素体。周边细胞含有的反光球体很少或没有，黑素体较多。描述了上皮层内一群游走的吞噬细胞。布鲁赫膜呈现三层结构，而非大多数脊椎动物中常见的五层结构。面对布鲁赫膜的脉络膜毛细血管内皮非常薄，但仅显示少量窗孔。
