Search results
Results From The WOW.Com Content Network
Menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the ...
The luteal phase is characterized by changes to hormone levels, such as an increase in progesterone and estrogen levels, decrease in gonadotropins such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH), changes to the endometrial lining to promote implantation of the fertilized egg, and development of the corpus luteum. In the ...
A rise in pituitary FSH caused by the disintegration of the corpus luteum at the conclusion of a menstrual cycle precipitates the recruitment of five to seven class 5 follicles to participate in the next cycle. These follicles enter the end of the prior menstrual cycle and transition into the follicular phase of the next one. The selected ...
A woman’s monthly cycle has four parts: menstrual, follicular, ovulation and luteal phases. The ovaries make eggs, and the area around the developing egg is called the follicle.
Polymenorrhea is usually caused by anovulation (failure to ovulate), an inadequate or short luteal phase, and/or a short follicular phase. [ 4 ] [ 3 ] [ 5 ] Polymenorrhea is common in puberty and adolescence due to the immaturity of the hypothalamic–pituitary–gonadal axis (HPG axis). [ 4 ]
The follicular phase (or proliferative phase) is the phase of the menstrual cycle during which the ovarian follicles mature. The follicular phase lasts from the beginning of menstruation to the start of ovulation. [12] [13] For ovulation to be successful, the ovum must be supported by the corona radiata and cumulus oophorous granulosa cells. [14]
This bistability is most obvious in the transition between the follicular and luteal phases, and arises from interactions between positive and negative feedback loops involving GnRH, LH, FSH, estrogen, and progesterone. The kisspeptin system creates a switch-like mechanism driving the transition from negative to positive feedback.
While the normal human menstrual cycle typically lasts 4 weeks (28 days, range 24–35 days) and consists of a follicular phase, ovulation, and a luteal phase followed by either menstruation or pregnancy, the anovulatory cycle has cycle lengths of varying degrees.