侧足厚蟹有髓鞘神经纤维的超微结构电镜观察

Ultrastructure of Myelinated Nerve Fibers of the Crab, Helice latimera

侧足厚蟹 (Helicelatimera)的有髓鞘神经纤维直径约在 5～ 1 2 μm之间 ,髓鞘厚约 2 μm左右。髓鞘由内外膜层和中间微管层组成。外膜层层数约 2 0层 ,排列紧密 ,微管层厚约 0 31 μm ,内膜层层数约 2 0层。轴突膜形成嵴 ,伸进轴腔内 ,在轴腔内还存在维管束和膜层束结构。在髓鞘结构中观察到两种类型的高嗜锇性区域 ,一种是由排列规则且明暗交替的膜层结构组成 ,另一种是非膜层结构组成。

The myelinated nerve fibers of the crab Helice latimera were about 5-12?μm in diameter with a sheath of about 2?μm. The sheath contained three parts: external membranes,microtube layers and internal membranes. There were about 20 layers of external and internal membranes and the microtube layers measured about 0.31?μm. Axolemma formed cristas which protruded into the axoplasm. There were membrane bunches and microtube bunches in the axoplasm of mylinated nerve fibers. There were two types of high osmiophil structures in nerve sheaths. One of these was lamellae, the other non-lamellae.