Lubińska L, Waryszewska J
Acta Neurobiol Exp (Wars). 1974;34(4):525-41.
All myelinated fibres along the unbranched pant of the phrenic nerve were teased and measured at regular intervals. At the proximal level, the size frequency distribution is bimodal with peaks at 2 and 7 micrometers. Fibres in most size classes exhibit a slight progressive tapering along their unbranched course in the nerve trunk. The degree of tapering is not identical in fibres of various calibre so that at the distal end of the nerve the pattern of size frequency distribution is altered. The volume of axoplasm of the total phrenic fibre population per unit length of the nerve decreases at the distal level to about 80 percent and the sum of axolemmal surface areas to about 90 percent of those found at the proximal level. Relevance of these results for interpretation of biochemical gradients of axonal components with various subcellular localizations is discussed. Below the sites of branching of individual fibres the total cross-sectional area of axoplasm in branches is practically equal to that of the parent fibre, whereas the sum axolemmal surface areas of branches is markedly increased.
对膈神经无分支段的所有有髓纤维进行分离，并定期测量。在近端水平，大小频率分布呈双峰状，峰值分别在2微米和7微米处。大多数大小类别的纤维在神经干的无分支行程中呈现出轻微的逐渐变细。不同直径的纤维变细程度并不相同，因此在神经远端，大小频率分布模式会发生改变。神经单位长度上膈神经纤维总体的轴浆体积在远端水平降至近端水平的约80%，轴膜表面积总和降至近端水平的约90%。讨论了这些结果对于解释具有不同亚细胞定位的轴突成分生化梯度的相关性。在单个纤维分支点以下，分支中轴浆的总横截面积实际上与母纤维的相等，而分支的轴膜表面积总和则显著增加。
