Ovulation
Ovulation is the process of discharging a mature ovum (egg) from an ovary after a Graafian follicle - representing the final stage of follicular development before ovulation - has been formed.
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2 Ovulation in animals 3 See also |
Ovulation in humans
In humans, normal ovulation happens 14 days before the start of the next menstrual cycle. Some women can feel a slight pain in their lower abdomen, known as Mittelschmerz or "intermenstrual pain".
In every menstrual cycle some ovarian follicles beginn maturation, but mostly only one will end as a Graafian follicle, growing rapidly under the influence of FSH and LH at the end of its developpement to a diameter of approximatly 15 mm, forming a "blister" on the surface of the ovary with a small spot without blood vessels, the "stigma". Encymatic processes and the growing pressure of its fluid-filled antrum lead to its rupture.
By this time, the oocyte has undergone its first meiotic division, leading to two cells of very different size: the secondary oocyte - containing all of the cytoplasmatic material of both daughter-cells - and the first polar body.
The second meiotic division follows at once without DNA-replication but will be arrested in the metaphase and will so remain until fertilization. The spindle apparatus of the second meitoc division appears at the time of Ovulation. If no fertilasation occurs, the oocyte will degenerate approximaly 24 hours after ovulation.
At ovulation, the mucous membrane of the uterus - named as "functionalis" - has reached its maximum size , and so have the endometrial glands, althouhg they are still non-secretory.
Knowing about the time of ovulation ist critical for all forms of "natural family planning".
Ovulation in animals
Some interesting aspects can be noted here:
See also