Corpus luteum
The corpus luteum , also known as the corpus luteum ( Latin corpus "body" and luteus "yellow"), is formed in mammals during ovulation ( follicle rupture ) of an egg cell. Under the influence of luteinizing hormone (LH), the mature egg cell leaves the egg follicle ; the rest - consisting of the endocrine granulosa cells lying in the wall of the ruptured follicle and immigrating theca cells - appears as a small yellow body and is called the corpus luteum. In the second phase of the monthly cycle, in addition to small amounts of the hormone estrogen, it increasingly produces progesterone , which is also called the luteal hormone and ensures that the pregnancy is maintained. In the first 7–8 weeks of pregnancy, progesterone is almost exclusively produced by the corpus luteum, after which this task is mainly taken over by the placenta , for whose development progesterone is also important.
Under the action of progesterone, the uterine lining prepares itself for a possible pregnancy and implantation of a fertilized egg cell . If pregnancy does not occur, the corpus luteum begins to shrink about 9 days after ovulation (→ luteolysis ), transforms into scar tissue and produces less and less progesterone, which ultimately leads to menstruation in humans . After its connective tissue transformation, it is referred to as corpus albicans (Latin albicare "to be white", "shimmer", plural corpora albicantia ). The multitude of transformed corpuscles gives the senile ovary its typical pitted surface structure.
If a fertilized egg cell implantation, the corpus luteum remains - in humans under the influence of human chorionic gonadotropin (hCG). It transforms into the corpus luteum graviditatis , which at the end of the first trimester of pregnancy takes up half of the entire ovary and ensures sufficient progesterone production until the placenta ( placenta ) is able to take over the hormone production itself through its trophoblastic portion .
A corpus luteum weakness is a common reason for this is that a woman is not pregnant or heaped very early miscarriage ( early abortions ) suffers. The experimental removal of the corpus luteum usually causes an early abortion.
literature
- Lois Jovanovic, Genell J. Subak-Sharpe: Hormones. The medical manual for women. (Original edition: Hormones. The Woman's Answerbook. Atheneum, New York 1987) From the American by Margaret Auer, Kabel, Hamburg 1989, ISBN 3-8225-0100-X , pp. 90, 102, 137, 142, 259, 266 and 370