Honjin R, Sakato S, Yamashita T
Arch Histol Jpn. 1977 Sep;40(4):321-32. doi: 10.1679/aohc1950.40.321.
The total number of myelinated and unmyelinated nerve fibers was counted in a montage of electron micrographs prepared to cover the entire profile of the mouse optic nerve in transverse section. Many astrocytic processes form a barrier structure all around the optic nerve. As a whole, the mouse optic nerve consists of one fascicle where the nerve fibers, the glia cells and their processes, and the capillaries are fitted closely together to fill substantially all of the available space. No tissue space accompanied with connective tissue septa penetrates into the fascicle, except for those situated around the arteriole and venule. The total number of 64,746 myelinated nerve fibers in the optic nerve in one side was counted. This corresponds to about 98.8% of the total number of the optic nerve fibers. The total number of 807 unmyelinated nerve fibers was also counted. This corresponds to about 1.2% of the total nerve fibers. The external diameter of every myelinated fiber, including the myelin sheath, was measured on the montage micrograph and its frequency distribution was examined. The diameter of the myelinated fibers ranges from 0.3 to 4.2 mu and its mean value is 0.96 mu. The frequency distribution of fiber diameter is unimodal with a peak at 0.7 to 0.9 mu. A regional heterogeneity in fiber size is found in the optic nerve. The nerve fibers in the peripheral area of the nerve are relatively small and uniform in diameter, whereas those in the central area show a fairly wide range in diameter.
在一组准备覆盖小鼠视神经横切面全貌的电子显微照片中，对有髓鞘和无髓鞘神经纤维的总数进行了计数。许多星形胶质细胞突起在视神经周围形成一个屏障结构。总体而言，小鼠视神经由一个束状结构组成，其中神经纤维、神经胶质细胞及其突起以及毛细血管紧密排列在一起，几乎填满了所有可用空间。除了位于小动脉和小静脉周围的那些组织间隙外，没有伴有结缔组织间隔的组织间隙穿透进入束状结构。一侧视神经中有髓鞘神经纤维的总数为64,746条。这大约相当于视神经纤维总数的98.8%。还计数了807条无髓鞘神经纤维。这大约相当于神经纤维总数的1.2%。在蒙太奇显微照片上测量了每根有髓鞘纤维（包括髓鞘）的外径，并检查了其频率分布。有髓鞘纤维的直径范围为0.3至4.2微米，平均值为0.96微米。纤维直径的频率分布是单峰的，在0.7至0.9微米处有一个峰值。在视神经中发现了纤维大小的区域异质性。神经外周区域的神经纤维相对较小且直径均匀，而中央区域的神经纤维直径范围相当宽。
