| Abstract: | In order to establish the moment of appearance of neuroblasts and ectoglia of the spinal cord the autoradiographic study with the use of H3-thymidine and C14-thmidine injected to pregnant mice with the intervals between injections 121/2 or 24 hours was undertaken. It was establised that spinal neurons were removed from the nervous tube beginning from the 10th up to 13th days of embroyogenesis. The motoneurons of the anterior horn were the first to appear (10th-12th days), the neurons of the intermideate zone were the next to appear (11th - 12th days) and the last were the neurons of posterior horn (13th day). Beginning from the 13th day of embryogenesis there appeared the ectoglia which migrated following meurblasts two days later. The saturation of the grey matter with glial cells and the saturation of the white matter with Schwann cells was brought about by means of additional multiplication at the site of the glioblasts removed from the nervous tube. The main function of the matrix layer neuroepithelium of the nervous tube as a provider of cells to the spinal cord terminated on the 15th day of embryogenesis. |
