第7卷‧第4期,
198310
, pp. 446-454
成年大白鼠視神經之神經細胞與神經髓鞘
- 作者:
劉克明
- 作者服務機構:
高雄醫學院解剖學
- 中文摘要:
六隻成年大白鼠於灌流固定後,其視神經與視交叉剝離,經過餓酸再固定、脫水、塑膠包埋等例行電子顯微鏡標本處理過程。視神經的半薄,橫切面照相後,應用蘋果牌電腦聯合 HIPAD Digitizer 計量與分析。 結果顯示,視神經纖維與軸突的面積與直徑、神經髓鞘的面積與厚度,皆沿著視神經的走向,由眼球後方往大腦端呈現局部性厚薄程度不一致的增加。於橫切面的中央部位和靠近眼球端,有相當多的細、髓鞘薄的小神經纖維。在橫切面的周邊部位和近於視交叉端,則富於粗、髓鞘厚的大神經纖維。 神經髓鞘的厚度與神經膠細胞的數目之間,無明確的正比關係;髓鞘與軸突直徑之間也無絕對正比關係。沿著神經走向;不同部位神經組織的區域百分比,軸突與髓鞘的比例由眼球端往視交叉端增加,但神經膠細胞與血管的比例減少。 神經髓鞘形成的程度沿著視神經不同部位而有變化,這種局部的神經纖維厚度的變化,可能受到數種內在的及外在的因素的影響。這些因素能隨著動物的成長而持續著且會變更其影響的程度。
- 英文摘要:
After perfused with aldehydes, the optic nerve and chiasm of six Charles River strain adult rats weredissected, postfixed, dehydrated and embedded in Araldite using routine electron microscopic procedures.The semithin, transverse section of the nerve was cut, photographed and quantitated with an Apple com-puter conjoined with a HIPAD Digitizer. The result showed that the area and diameter of fibers and axons, the area and thickness of myelinsheaths were rostrocaudally increased with peaks and troughs along the optic nerve. The central locationof the cross section, and the area near the orbital end were compacted with small, thin myelinated fibers.Around the periphery of the cross section, and near the chiasm, there was high percentage of big, thickmyelinated fibers. Neither precisely linear correlation occurred between the thickness of myelin sheathsand number of neuroglial cells, nor between myelin sheaths and diameter of axons. The percent area ofaxon and myelin sheaths increased from orbital to chiasmal end, but, the percent area of glial cells andblood vessels decreased from orbital to chiasmal end. The rate of myelination was different at variable sites along the optic nerve. The regional variationsof fiber thickness were caused by local effects of several endogenous and exogenous factors, which may bepersisted and modified with the growth of animals.
- 中文關鍵字:
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- 英文關鍵字:
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