摘要
本实验取材自14例人工流产的正常人胎,胎龄13～32周,坐高(CR)8.3～33cm。于大脑半球距状裂中部,作冠状切面扫描电镜观察。在胎龄13周(CR8.3cm),17区脑壁从内向外由脑室带、脑室下带、中间带、皮质板、缘带组成。随着胎龄增长,上述5带发生一系列变化,1.脑室带逐渐变薄,细胞分裂活动逐渐减少,最后分化为单层的室管膜上皮。2.脑室下带和中间带逐渐被纤维束取代而成白质。3.皮质板随胎龄增长而增厚并分化,胎龄21周(CR20cm)时,皮质板下部首先出现第Ⅵ、Ⅴ层;23周(CR22cm)时,皮质板中部出现第Ⅳ层;26周(CR25cm)时,皮质板上部出现第Ⅲ、Ⅱ层。4.缘带原位分化为第Ⅰ层。
Tissue was obtained from 14 aborted human fetuses, ranging from 13-32 weeks of gestation (wg). The crown-rump length (CR) ranged from 8.3-33 cm. Frontal sections of the specimens were prosessed for SEM and observation were focused on the areas adjacent to the middle part of the calcarine fissure.
At 13 wg (CR 8.3 cm), the visual cortex (area 17) was composed of five zones: viz., the ventricular zone, the subventricular zone, the intermediate zone, the cortical plate and the marginal zone. These five zones showed a series of transformations with increasing age. 1) The ventricular zone became progressively thinner, mitotic activity of the ventrieular cells decreased progressively and finally the ventricular ceils differentiated into a single layer of ependymal cells. 2) The subventricular zone and the inter mediated zone were replaced by fiber bundles of white matter. 3) The cortical plate increased in width, exhibited the greatest growth rate, and became differentiated. At 21 wg (CR 20cm), the lower part of the cortical plate first gave rise to laminae VI and V. At 23 wg (CR 22cm), lamina Ⅳ was established in the middle part of cortical plate. At 26 wg (CR 25cm), laminae Ⅲ and Ⅱ could be identified in the upper part of cortical plate. 4) The marginal zone transformed into lamina Ⅰ at its original site.
出处
《解剖学报》
CAS
CSCD
北大核心
1990年第1期39-43,共5页
Acta Anatomica Sinica
基金
国家自然科学基金
关键词
细胞构筑
视皮质(17区)
扫描电镜
人胎
Cytoarchitecture
Visual cortex (area 17)
Scanning electron microscopy
Human fetuses
