Introduction:
The blastocyst is a structure formed in the early embryogenesis of animals, after the formation of the morula. It is a specifically mammalian example of a blastula. It possesses an inner cell mass (ICM), or embryoblast, which subsequently forms the embryo, and an outer surface of cells, or trophoblast, which later types the placenta. The trophoblast surrounds the inner cell mass and a fluid-filled blastocyst cavity known as the blastocoele or the blastocystic cavity. The human blastocyst includes 70-100 cells.
The blastocyst consists of two primary cell types:
The former is the source of embryonic stem cells and gives increase to all later structures of the adult organism. The latter combines with the maternal endometrium to type the placenta in eutherian animals.
Risks of blastocyst transfer:
Blastocyst transfer can be extremely successful for some categories of women, but it isn't right for everyone and does have some drawbacks:
Blastocyst transfer may not be appropriate for all women and not all UK centres are able to offer it. Different treatments have different policies and working arrangements. Ask your clinic whether they offer this service and how they decide who is suitable for it.
Blastocyst Implantation:
An intimate cross-talk between the embryo and the uterus is required for blastocyst implantation. This process, which includes of an interaction between trophoblast cells and endometrium, can only take position in a restricted period of time, termed "window of receptivity". It is initially dependent upon the presence of estrogen and progesterone, although further morphological and biochemical changes are evoked within the uterine walls by alerts from the embryo and invading trophoblast. The "window of receptivity" in humans is presumed to span days 20–24 of the menstrual cycle.
When the embryo reaches the blastocyst stage it develops two distinct populations of cells. The external cell mass, called the trophectoderm, and the inner cell mass. There is also a fluid filled cavity. Actually Implantation begins first with attachment (adplantation) of the blastocyst through the external trophopoblast cells to the uterine lining. Following adplantation, trophoblast cells on the outside differentiate into syncitiotrophoblasts which get the uterine endometrium. The blastocyst then moves into the endometrium, initially partially buried, and on completion of implantation, is completely buried in the endometrium. The site of implantation is noticeable on the surface by a "plug"
Conclusion:
Blastocyst can be acquired in sequential culture media in the absence of coculture and serum. Transfer of blastocyst in IVF will facilitate high PRs while limiting the number of embryos transferred and therefore reduces the risk of multiple gestations. And now you want to know more about the blastocyst you should visit the Physiology articles in that you can view whatever implantation and transfers are used.
The blastocyst is a structure formed in the early embryogenesis of animals, after the formation of the morula. It is a specifically mammalian example of a blastula. It possesses an inner cell mass (ICM), or embryoblast, which subsequently forms the embryo, and an outer surface of cells, or trophoblast, which later types the placenta. The trophoblast surrounds the inner cell mass and a fluid-filled blastocyst cavity known as the blastocoele or the blastocystic cavity. The human blastocyst includes 70-100 cells.
The blastocyst consists of two primary cell types:
- the inner cell mass, also known as the "embryoblast" (this part of the embryo is used in stem cell research)
- the trophoblast, a layer of cells around the inner cell mass and the blastocyst cavity.
The former is the source of embryonic stem cells and gives increase to all later structures of the adult organism. The latter combines with the maternal endometrium to type the placenta in eutherian animals.
Risks of blastocyst transfer:
Blastocyst transfer can be extremely successful for some categories of women, but it isn't right for everyone and does have some drawbacks:
- Blastocyst transfer can outcome in a higher likelihood of becoming pregnant when compared with 2–3 day embryo transfer in certain groups of women.
- However, if you opt for blastocyst transfer, you may not get any embryos that develop to the blastocyst stage.
- There may also be fewer embryos to freeze.
- If your embryos do develop to the blastocyst stage and multiple blastocyst transfer is used, you are at greater risk of producing twins.
Blastocyst transfer may not be appropriate for all women and not all UK centres are able to offer it. Different treatments have different policies and working arrangements. Ask your clinic whether they offer this service and how they decide who is suitable for it.
Blastocyst Implantation:
An intimate cross-talk between the embryo and the uterus is required for blastocyst implantation. This process, which includes of an interaction between trophoblast cells and endometrium, can only take position in a restricted period of time, termed "window of receptivity". It is initially dependent upon the presence of estrogen and progesterone, although further morphological and biochemical changes are evoked within the uterine walls by alerts from the embryo and invading trophoblast. The "window of receptivity" in humans is presumed to span days 20–24 of the menstrual cycle.
When the embryo reaches the blastocyst stage it develops two distinct populations of cells. The external cell mass, called the trophectoderm, and the inner cell mass. There is also a fluid filled cavity. Actually Implantation begins first with attachment (adplantation) of the blastocyst through the external trophopoblast cells to the uterine lining. Following adplantation, trophoblast cells on the outside differentiate into syncitiotrophoblasts which get the uterine endometrium. The blastocyst then moves into the endometrium, initially partially buried, and on completion of implantation, is completely buried in the endometrium. The site of implantation is noticeable on the surface by a "plug"
Conclusion:
Blastocyst can be acquired in sequential culture media in the absence of coculture and serum. Transfer of blastocyst in IVF will facilitate high PRs while limiting the number of embryos transferred and therefore reduces the risk of multiple gestations. And now you want to know more about the blastocyst you should visit the Physiology articles in that you can view whatever implantation and transfers are used.