[Role of the rat visceral yolk sac in the realization of trophic function].
The villous and smooth parts of visceral yolk sac (VYS) were studied in rat in the second half of gestation using electron microscopy and morphometry. It was shown that the changes in VYS epithelium took place unidirectionally: the length of microvilli was decreased, while the coefficient characterizing epitheliocyte capacity for absorption was diminished. This was accompanied by an increase in the index of surface density of the apical transport system and absorption vacuoles. These findings are indicative of the activation of endocytosis in VYS in the second half of gestational period. Different amplitude of the changes of the parameters studied in villous and smooth parts of VYS are associated with their topography and formation of chorio-allantoic and yolk sac placentas in rat embryogenesis.
Dubinina
N N
NN
Sklainov
Iu I
IuI
Bychkova
N A
NA
D000818:Animals; D004705:Endocytosis; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D015017:Yolk Sac / Q000502:physiology* / Q000648:ultrastructure*