The corpus luteum (Latin for "yellow body") is a small, temporary endocrine structure in mammals that develops from an ovarianfollicle after it has released a mature egg.
The corpus luteum secretes the hormoneprogesterone, which thickens the uterine lining in preparation for the fertilized egg. If the egg is not fertilized, the corpus luteum stops secreting progesterone and decays after approximately 12 days. It then degenerates into a corpus albicans, which is a mass of fibrotic scar tissue. The uterine lining sloughs off without progesterone and is expelled through the vagina. This is called menstruation.
If fertilized, however, the egg secretes the hormone human chorionic gonadotropin (hCG). hCG signals the corpus luteum to continue progesterone secretion, thereby maintaining the thick lining of the uterus, and providing an area rich in blood vessels in which the zygote can develop. From this point on, the corpus luteum is called the corpus luteum graviditatis. The introduction of the hormone Prostaglandin at this point causes the death of the cl and the abortion of the fetus.
In the ovary, the corpus luteum secretes estrogens and progesterone, which are steroid hormones responsible for the thickening of the endometrium and its development and maintenance, respectively.
The introduction of the hormone prostaglandin at this point causes the degeneration of the corpus luteum and the abortion of the fetus.
The corpus luteum is typically very large relative to the size of the ovary; in humans, the size of the structure ranges from under 2 cm to 6 cm in diameter.
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