[The anomalous development of the nervous system of the human embryo at 3.2 mm of length].
Serial histological preparations of a human embryo of 3.2 mm parieto-coccygeal length were studied. The morphological organization of the embryo had a combination of signs typical for the 10, 11 and 12th stages of the human development. Neurulation in the abnormal embryos was completed at the stage of 6 somites which is 2-3 days earlier than in a normally developing embryo. The embryo had no neural tube and the neuroepithelial cells represented a homogeneous cord without signs of striatal or nuclear organization. The embryo was found to have germs of the ocular vesicles, induced germs of the lens, olfactory and auditory placodes. Disturbances in the differentiation of the chordomesoderm and germs of branchial pockets took place. The changes observed are supposed to be a result of relaxation reactions of the neuroepithelium of the neural tube in response to nonspecific mechanico-chemical actions at the end of neurulation.
Savel'ev
S V
SV
D006801:Humans; D008648:Mesoderm / Q000166:cytology; D009421:Nervous System Malformations; D009436:Neural Tube Defects / Q000196:embryology
Anomal'noe razvitie nervnoĭ sistemy u émbriona cheloveka 3,2 mm dlinoĭ.