Keltarauhasessa

Keltarauhasessa, also known as the corpus luteum in English, is a temporary endocrine structure that forms in the ovary of female mammals after ovulation. It plays a crucial role in the menstrual cycle and early pregnancy. The name "corpus luteum" literally translates to "yellow body" in Latin, referring to its characteristic yellowish color.

Following the release of an egg from a mature ovarian follicle during ovulation, the remaining follicular cells undergo a process of luteinization. These cells transform and enlarge, forming the corpus luteum. Its primary function is to produce progesterone, a hormone essential for preparing the uterine lining (endometrium) for potential implantation of a fertilized egg. Progesterone helps maintain the endometrium, making it receptive and preventing its shedding.

If fertilization and implantation occur, the developing embryo will produce human chorionic gonadotropin (hCG). This hormone signals the corpus luteum to continue producing progesterone, thereby sustaining the pregnancy until the placenta takes over this function.

If fertilization does not happen, the corpus luteum will degenerate approximately 10-14 days after ovulation. This degeneration leads to a drop in progesterone and estrogen levels. This hormonal decline triggers the shedding of the uterine lining, resulting in menstruation, and the start of a new ovarian cycle. The remnants of the degenerated corpus luteum form a scar tissue called the corpus albicans.