Blastocyst


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Related to Blastocyst: blastocyst transfer

blastocyst

[′blas·tə‚sist]
(embryology)
A modified blastula characteristic of placental mammals.

Blastocyst

 

blastodermic sac, a stage in the development of mammal embryos, including humans, that arises as a result of cleavage of the fertilized ovum. The blastocyst is a hollow sac. An aggregate of cells—a node, analogous to the blastula of other animals—is found on one side of it. The outer wall of the blastocyst forms the trophoblast.

References in periodicals archive ?
It is possible to establish three different types of stem cells, including ES cells, from thes three cell types in the blastocyst.
Embryonic stem cells are an in vitro copy of embryonic cells at the blastocyst stage, called the inner cell mass (18,19).
PRECIS: Blastocyst transfer is an efficient embryo transfer method associated with satisfactory pregnancy outcomes, and performing blastocyst transfer may have benefits because morphologic assessment on day 3 has limited predictive value for subsequent embryonic development.
Patients aged 41-42 years should receive single blastocyst transfer if euploid embryos are available, or no more than four cleavage-stage embryos or three blastocysts.
It is recommended that poor quality embryos be cultured separately and subsequently transferred or frozen if they could develop to high quality blastocysts.
However, blastocyst yield at d 7 not different in the three treatments, the highest percentage was when BSA was added to the culture medium (TABLE III).
Despite numerous studies and generally accepted opinion that the blastocyst transfer increases the success rate, the published data still show that this hypothesis is not, at least partly, true [31].
Although the blastocyst stage of human embryos has been extensively studied and documented, what happens beyond the seventh day of fertilization - when the embryo must implant itself into the uterus to survive - still remains shrouded in mystery.
The blastocyst comprises three cell types: cells that will develop into the placenta and allow the embryo to attach to the womb; and cells that form the yolk sac, which provides nutrients to the developing fetus; and the epiblast comprising the naive cells that will develop into the future body.