14,5th stage
Abnormal human embryo brain Mallory slices. 6,5 mm CRL , 14,5 Carnegie stage (32-35 days, 5th pcw).
Neurulation abnormalities leads in the complex lethal embryonic pathologies: the neural tube, located ventrally to the rostral neuropore was open and the neural cavity communicated with the amniotic fluid; there are telencephalon aplasia and diencephalon hypoplasia, also as absence of the eyes and crystalline lenses anlages.
Abnormal human embryo brain Mallory slices. 6,5 mm CRL , 14,5 Carnegie stage (32-35 days, 5th pcw); Neurulation abnormalities leads in the complex lethal embryonic pathologies: the neural tube, located ventrally to the rostral neuropore was open and the neural cavity communicated with the amniotic fluid; there are telencephalon aplasia and diencephalon hypoplasia, also as absence of the eyes and crystalline lenses anlages
To the stage of 32-35 postconceptional days of normal development telencephalon hemispheres, epiphysis, infundibulum and hypophysis are is shaped. The 6,5 case demonstrated only abnormal neurohypophysis (Rathke's) pouch. Neuroepithelium located ventral to the rostral neuropore was comprised as homogeneous layer everted to the amniotic fluid with its apical surface. Olfactory placodes accreted with the lateral of the neural plate rims. Eyes and eye lens anlages were absence, which evidenced for the early stage origin of abnormality. Neural tube was opened at the level of rostral neuropore, thus telencephalon hemispheres and basal structures weren’t identified. Additional abnormality was registered in the fourth ventricle organization – as distinct from normal development, when neural tube dorsally opened from the level of 1-2 rhombomere to the caudal level of the 7th rhombomere – fourth ventricle cavity was closed. Thus additionally changes in the segmentation of proneuromere structures ventrally to the neuropore were described.
For more details see С.В. Савельев "Эмбриональная патология нервной системы", 2007 г., стр. 70- 75
To the stage of 32-35 postconceptional days of normal development telencephalon hemispheres, epiphysis, infundibulum and hypophysis are is shaped. The 6,5 case demonstrated only abnormal neurohypophysis (Rathke's) pouch. Neuroepithelium located ventral to the rostral neuropore was comprised as homogeneous layer everted to the amniotic fluid with its apical surface. Olfactory placodes accreted with the lateral of the neural plate rims. Eyes and eye lens anlages were absence, which evidenced for the early stage origin of abnormality. Neural tube was opened at the level of rostral neuropore, thus telencephalon hemispheres and basal structures weren’t identified. Additional abnormality was registered in the fourth ventricle organization – as distinct from normal development, when neural tube dorsally opened from the level of 1-2 rhombomere to the caudal level of the 7th rhombomere – fourth ventricle cavity was closed. Thus additionally changes in the segmentation of proneuromere structures ventrally to the neuropore were described.
For more details see С.В. Савельев "Эмбриональная патология нервной системы", 2007 г., стр. 70- 75
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