blastocyst The developmental stage of the fertilized ovum by the time it is ready to implant; formed from the morula and consists of an inner cell mass, an internal cavity, and an outer layer of cells (the trophoblast).
blastocyst
[Gk. blastos, sprout + kystis, sac]
An embryonic stage in mammals; a hollow ball of cells produced one week after fertilization in humans.
blastodisc ...
blastocyst - cleavage stage mammalian embryo; a hollow ball of cells made of outer trophoblast cells and an inner cell mass.
blastoderm - cell layer formed during cleavage of telolecithal and centrolecithal eggs.
Blastocyst the hollow ball stage of embryonic development
(blasto = bud‚ sprout)
Botanist a person who studies plants
(botan = grass‚ pasture) ...
Blastocysts
A blastocyst is a stage of development of an embryo when it is around five days old and made up of about 100 cells.
blastocyst An early stage of embryonic development consisting of a hollow ball of cells;a small ball of cells representing an early stage of embryonic development.
The blastocyst has two parts:
the inner cell mass, which will become the baby, and
the trophoblast, which will
develop into the placenta and umbilical cord
and begin to secrete human chorionic gonadotropin (HCG).
In the early blastocyst, this initial, imprinted X-inactivation is reversed in the cells of the inner cell mass (which give rise to the embryo), and in these cells both X chromosomes become active again.
The embryo proper begins to form from an inner cell mass within the blastocyst. Some parts of the blastocyst will form the extra embryonic membranes such as the amnion, chorion and parts of the placenta.
As development progresses from the embryonic cell, which is derived from the blastocyst of an embryo, these cells are isolated from the blastocyst and are put in culture where they can divide.
Egg, 2-cell, 8-cell, and blastocyst cRNAs will be generated via in vitro transcription from existing cDNA libraries, while postimplantation mRNAs will be isolated from whole or dissected fetuses, neonates, juveniles, and adults.
implantation The process in which the blastocyst embeds in the endometrium. PICTURE
incomplete dominance A type of inheritance in which the heterozygote has a phenotype intermediate to those of the homozygous parents. PICTURE ...
(Science: biology, gynaecology) The onset of pregnancy, marked by implantation of the blastocyst, the formation of a viable zygote.
Origin: L. Conceptio ...
gene into cultured embryonic stem cells, searching through the thousands of resulting clones for one in which the crippled gene exactly replaced the normal one (by homologous recombination), and inserting that cell back into a mouse blastocyst.
 See also: Cells, Cell, Human, Organ, Embryo
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