崇安髭蟾视网膜的组织结构

RETINAL ORGANIZATION IN VIBRISSAPHORA LIUI

在光镜和电镜下观察了崇安髭蟾（Ｖｉｂｒｉｓｓａｐｈｏｒａ ｌｉｕｉ）视网膜的组织结构，着重探讨感光细胞和神经节细胞的形态、计数及分布。结果表明，其视网膜组织结构符合脊椎动物的基本模式。视网膜总厚度为１４３μｍ。感光细胞总数约２５０万，几乎全是视杆，似视锥的光感受器不超过３％。神经节细胞总数约２１万，从节细胞等密度图上看出在视盘背侧沿鼻颞轴有一个高密区，即为视条（ｖｉｓｕａｌｓｔｒｅａｋ）。比较神经节细胞的密度分布及光镜和电镜下感光细胞形态结构及其分布，认为崇安髭蟾视网膜的结构特征与其夜间活动的生活习性是相适应的。

The retinal organization in Vibrissaphora liui was studied with emphasis on the morphology, number and distribution of photoreceptors and ganglion cells. The results show that the retinal layered structure in V. liui accords with the typical pattern of that in vertebrates. The thickness of the retina in V. liui is approximately 143μm. There are about 2. 5 millions photoreceptors per retina, which are mostly rods, only a few cones (less than 3% of the total). The red rods are more than the green ones. There are about 210 thousands ganglion cells per retina. The isodensity map of the retinal ganglion cells shows that the area of highest cell density is a long area(visual streak), it was located at the dorsum of the optic disc. The density of ganglion cells is higher along the naso-temporal axis of the retina, and decreases dorsally and ventrally. The comparative study of the morphology of photoreceptors was made under LM, SEM and TEM. We concluded that the retina in V. liui which is a nocturnal species is principally adapted to operate in low intensities of light.