As well as physiologic differences in the macroscopic appearance of the placenta between species, the microscopic structure of the interaction between fetal and maternal tissues also differs between species.
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As well as physiologic differences in the macroscopic appearance of the placenta between species, the microscopic structure of the interaction between fetal and maternal tissues also differs between species. The interface between the chorion and uterus can consist of different numbers and arrangements of epithelial cells and basal laminae on both the fetal and maternal sides. Beneath the layers of basal laminae there are further layers of connective tissue that contain high densities of blood capillaries.