animal pole


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animal pole

[′an·ə·məl ‚pōl]
(cell and molecular biology)
The region of an ovum which contains the least yolk and where the nucleus gives off polar bodies during meiosis.
References in periodicals archive ?
As a result of chlorpyrifos treatment in this sensitive period, a compact extralarval cap, largely comprised of pigmented cells, formed at the animal pole, and the blastocele, indeed the larva itself, was correspondingly diminished because of both cell extrusion and compaction.
Before its loss, the cap was connected to the animal pole of the larva by a thin stalk.
Cell migration itself appears not to be an actual target for the effects of chlorpyrifos, because the movement of cells continued in the normal direction along the animal--vegetal axis, albeit that the cells were migrating into the enormous extralarval cell mass through an abnormal structure, the thin stalk attached to the animal pole.
After fertilization, these patterns change and [beta]-tubulinrich streams oriented toward the animal pole are formed along the outer cortex of the embryo.
Fine structure and early fertilization changes of the animal pole in eggs of the river lamprey, Lampetra fluviatilis.
Fertilization in the medaka egg is followed by a cortical granule reaction and a contraction, during which the ooplasm and its contents appear to be pulled toward the animal pole.
In all regions of the egg except the animal pole, all the microtubules were within 2-3 [[micro]meter] of the surface of the egg and were visible in a single optical section.
The suggestion that microtubules are involved in the segregation of oil droplets toward the vegetal pole is inconsistent with the hypothesis that this segregation is caused simply by the bulk flow of ooplasm in the opposite direction, that is, toward the animal pole (Sakai, 1965).
Thus, another objective of the present study was to monitor the movement of injected droplets of five fluids that differ widely in their chemical and physical properties; the eggs in the present study were oriented with either their animal pole or their vegetal pole uppermost.
The results illustrated in Figure 1B (a representative example; n = 12), confirm the earlier findings from the animal pole (3) and the vegetal pole (2).