Crossword clues for blastula
The Collaborative International Dictionary
Blastula \Blas"tu*la\, n. [NL., dim. of Gr. blasto`s a sprout.] (Biol.) That stage in the development of the ovum in which the outer cells of the morula become more defined and form the blastoderm.
Douglas Harper's Etymology Dictionary
embryonic state, 1875, Modern Latin, from Greek blastos "sprout, germ" + diminutive ending -ula.
Wiktionary
n. (context embryology English) An early form in the development of an embryo, consisting of a spherical layer of cells filled with fluid; a blastosphere.
WordNet
n. early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is composed of a single layer of cells; during this stage (about eight days after fertilization) implantation in the wall of the uterus occurs [syn: blastodermic vesicle]
[also: blastulae (pl)]
Wikipedia
The blastula (from Greek βλαστός (blastos), meaning " sprout") is a hollow sphere of cells, referred to as blastomeres, surrounding an inner fluid-filled cavity called the blastocoele formed during an early stage of embryonic development in animals. Embryo development begins with a sperm fertilizing an egg to become a zygote which undergoes many cleavages to develop into a ball of cells called a morula. Only when the blastocoele is formed does the early embryo become a blastula. The blastula precedes the formation of the gastrula in which the germ layers of the embryo form.
A common feature of a vertebrate blastula is that it consists of a layer of blastomeres, known as the blastoderm, which surrounds the blastocoele. In mammals the blastula is referred to as a blastocyst. The blastocyst contains an embryoblast (or inner cell mass) that will eventually give rise to the definitive structures of the fetus, and the trophoblast, which goes on to form the extra-embryonic tissues.
During the blastula stage of development, a significant amount of activity occurs within the early embryo to establish cell polarity, cell specification, axis formation, and regulate gene expression. In many animals such as Drosophila and Xenopus, the mid blastula transition (MBT) is a crucial step in development during which the maternal mRNA is degraded and control over development is passed to the embryo. Many of the interactions between blastomeres are dependent on cadherin expression, particularly E-cadherin in mammals and EP-cadherin in amphibians.
The study of the blastula and of cell specification has many implications on the field of stem cell research as well as the continued improvement of fertility treatments. Embryonic stem cells are a field which, though controversial, have tremendous potential for treating disease. In Xenopus, blastomeres behave as pluripotent stem cells which can migrate down several pathways, depending on cell signaling. By manipulating the cell signals during the blastula stage of development, various tissues can be formed. This potential can be instrumental in regenerative medicine for disease and injury cases. In vitro fertilisation involves implantation of a blastula into a mother’s uterus. Blastula cell implantation could potentially serve to eliminate infertility.
Usage examples of "blastula".
So it should be quite easy to take an unfertilized turkey egg, inject a dodo blastula, and, with luck, hatch a perfectly viable dodo chick.
It is only during gastrulation, after the egg has divided and redivided many times and shaped itself into a hollow ball of cells called a blastula, that the development of organs, limbs and other body parts begins.
There are many more that can be detected in the early check, before the blastula is implanted in the replicator bed and starts forming its placenta.
Around a cluster of stars called the Blastula Luz, I prepared my long passage to the Rosette Nebula in the Orion Arm.
I penetrated the Blastula and segued to the thickspace at its nearly hollow center.
It provided automated storage and retrieval of the hundreds of bar-coded DNA samples, embryos, and blastulas that the geneticists had to keep track of.
All Kenneth had to do was retrieve the blastulas that Tomila had earmarked for incineration, before the lab attendant did.
The blastulas were dubbed the 1-1-2041s, and everything about their lives became the subject of intense public scrutiny and fascination and self-righteous horror.
Apparently, one of the master Scientists was trying to cark Scutari blastulas into a shape more to his liking.
It was an experiment of the Scientists to interfere with Scutari gastrulation, coaxing the blastulas that they had somehow acquired to develop more like sea urchins or Darghinni or even human beings.
The blastulas were dubbed the 1-1-2041s, and everything about their lives became the subject of intense public scrutiny and fascination and self-righteous horror.
This part of Sunulok had grown an array of geometrically staggered coral blastulas where dozens of smaller villips lay quiescent.
Fluids leaked from the dovin basal blastulas, trailing behind like frozen streamers.
They made a blastula inside my skull, dividing again and again, with their animal pole at my left ear and their vegetal pole at my right.
The ship had contracted, necks reduced in length, tail and nose become blunt nubbins, grooves indenting the circumference of the second homeball like the cell divisions of a blastula.