Volume : V, Issue : VIII, August - 2016

CYTOARCHITECTURE OF HUMAN FOETAL HIPPOCAMPUS

Dr. K. R. S. Prasad Rao

Abstract :

 Background: The hippocampus is empirically assumed to have different functions, of which the best known are: the representation of self–location in cognitive dimensions, and the storage and retrieval of memory.Materials and methods:Eighteen human foetal ains from 15 to 39 weeks used. Hippocampus dissected out of Brain, specimens were processed into paraffin blocks, sectioned (10 µm thick), and stained using Haematoxylin and Eosin . Cytometric analysis was done through binocular microscope using micrometers. Results: The lamellae of the hippocampus were cytometrically evaluated for thickness of various layers and neuronal sizes , form and density in different gestational periods .Conclusions: This study confirmed the existence of differences in nerve fiber distribution among the subfields of the hippocampus which is attributed to differences in the emyonic development processes and to the selectivity of the different connections. In the hippocampus as in the rest of the ain, neurons populate, region differentiated accordingly their morphology dendritic arborization or synaptic, histo chemical properties. Regional differentiation based on neuronal parameters of size form and density and thickness was examined. In correlation values between hippocampus sub fields in each size separately. For unknown reason in human neonates and in very young infants, hippocampal sub field neurons are qualitatively most differentiated form. CA3 neurons qualitatively close behind CA2 in form differentiation. CA1 neurons appear immature with poor differentiation rendering them difficult quantitatively.As explained in material and methods foetus ains processed and slides prepared. they were examined under microscopewith micrometer.At 15 weeks gestation showed a uniform cellular pattern, There is no distinction of the other layers. in 18 weeks gestation the hippocampus showed 3 zones i.e. ependymal, mantle, marginal zones. At full term it reaches adult hippocampus appearance with pyramidal layer molecular and polymorphic above and below. In the pyramidal layer there is a variation in the neuron size in CA3, CA2, CA1 sub fields. The neuron size in CA1 sub field showed 9.6 μ at 22 weeks, 14.4μ at full term. Dentate gyrusby full term 8 cell thick layer measuring 110.4μ has been observed.The plexiform and molecular layer though noticed at 20 weeks but their definite configuration is observed only at full term. The cells in the plexiform layer are scanty and small,

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Article: Download PDF   DOI : 10.36106/ijsr  

Cite This Article:

DR.K.R.S.PRASAD RAO CYTOARCHITECTURE OF HUMAN FOETAL HIPPOCAMPUS International Journal of Scientific Research,Volume : 5 | Issue : 8 |August 2016

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