First stages of segmentation of a mammalian embryo. Semidiagrammatic. z.p. Zona pellucida. p.gl. Polar bodies. a. Two-cell stage. b. Four-cell stage. c. Eight-cell stage. d, e. Morula stage.
A polar body is a small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized. It is named from its polar position in the egg.
When certain diploid cells in animals undergo cytokinesis after meiosis to produce egg cells, they sometimes divide unevenly. Most of the cytoplasm is segregated into one daughter cell, which becomes the egg or ovum, while the smaller polar bodies only get a small amount of cytoplasm. They frequently die and disintegrate by apoptosis, but in some cases remain and can be important in the life cycle of the organism.[1]
^Schmerler, S.; G.M. Wessel (2011). "Polar bodies—more a lack of understanding than a lack of respect". Mol. Reprod. Dev. 78 (1): 3–8. doi:10.1002/mrd.21266. PMC 3164815. PMID 21268179.
A polarbody is a small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized...
that it was probably a polarbody twin. The authors were unable to predict whether a healthy fetus could result from a polarbody twinning. However, a study...
Polarbody biopsy is the sampling of a polarbody of an oocyte. It was first applied clinically in humans in 1987 after extensive animal studies. A polar...
composition for a body of ice to be termed a polar ice cap, nor any geological requirement for it to be over land, but only that it must be a body of solid phase...
with bodies moving around a central point, or phenomena originating from a central point, are often simpler and more intuitive to model using polar coordinates...
chromosome) and extrude its first polarbody. The oocyte will only continue through meiosis and extrude its second polarbody once it is fertilized. Ovulation...
{\displaystyle K} is a bounded convex body containing the origin O {\displaystyle O} in its interior, the polarbody K ∗ {\displaystyle K^{*}} is { u : ⟨...
the four meiotic products are typically eliminated by extrusion into polarbodies, and only one cell develops to produce an ovum. Because the number of...
A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly...
in all (4C). When meiosis I is completed, one secondary oocyte and one polarbody is created. Primary oocytes have been created in late fetal life. This...
meiosis II. In oocytes, one sister chromatid is segregated into the second polarbody, while the other stays inside the egg. During spermatogenesis, each meiotic...
rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates Polar climate, the climate common in polar regions...
The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can...
report in 2001 on worldwide use of PGD since 1990 reported that embryo or polarbody biopsy had occurred in more than 3000 clinical cycles, with a 24% pregnancy...
facultative parthenote reptiles is terminal fusion, in which a haploid polarbody produced as a byproduct of normal female meiosis fuses with the egg cell...
and the male pronucleus. The other product of meiosis is the second polarbody with only chromosomes but no ability to replicate or survive. In the fertilized...
polarbody and a large secondary oocyte. The secondary oocyte undergoes meiotic division II and that results in the formation of a second small polar...
starvation and other insults. Insemination Menstrual cycle Ova bank Ovulation Polarbody Pollination Pregnancy Spawn (biology) "Ovum". Biology Dictionary. BiologyOnline...
becomes one haploid ovum and typically two polarbodies, however one may later divide to form a third polarbody. In a male, meiosis starts with one diploid...
The Arctic fox (Vulpes lagopus), also known as the white fox, polar fox, or snow fox, is a small species of fox native to the Arctic regions of the Northern...
both of Earth's polar regions. Polar vortices also exist on other rotating, low-obliquity planetary bodies. The term polar vortex can be used to describe...
their chromosomes later to become diploid (2n) (by being fertilized by a polarbody, or by chromosome duplication without cell division), rather than by her...
complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the...
Polar cell may refer to: Polar cells, a constituent of atmospheric circulation Polarbody, a smaller cell by-product of egg formation in some animal species...
Polar Electro Oy (commonly known as Polar) is a Finnish manufacturer of sports training computers, particularly known for developing the world's first...
A polar bear plunge is an event held during the winter where participants enter a body of water despite the low temperature. In the United States, polar...
contains all of the cytoplasmic material and a smaller, inactive first polarbody. Meiosis II follows at once but will be arrested in the metaphase and...
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