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( Menstrual cycle)
The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age females. Overt menstruation (where there is blood flow from the vagina) occurs primarily in humans and close evolutionary relatives such as chimpanzees.[1] The females of other species of placental mammal have estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. This article focuses on the human menstrual cycle. The menstrual cycle is under the control of the hormone system and is necessary for reproduction. It may be divided into several phases menstruation, the follicular phase, and the luteal phase.[2] Ovulation defines the transition from the follicular phase to the luteal phase. Counted from the first day of menstrual flow, the length of each phase varies from woman to woman and cycle to cycle. The average cycles length is 28 days.[2] Hormonal contraception interferes with these normal hormonal changes with the aim of preventing reproduction. Stimulated by gradually increasing amounts of estrogen in the follicular phase, the lining of the uterus thickens. Follicles in the ovary begin developing under the influence of a complex interplay of hormones, and after several days one or occasionally two become dominant (non-dominant follicles atrophy and die). The dominant follicle releases an ovum, or egg, in an event called ovulation. After ovulation, the remains of the dominant follicle in the ovary become a corpus luteum; this body has a primary function of producing large amounts of progesterone. Under the influence of progesterone, the endometrium (uterine lining) changes to prepare for potential implantation of an embryo to establish a pregnancy. If implantation does not occur within approximately two weeks, the corpus luteum will involute, causing sharp drops in levels of both progesterone and estrogen. These hormone drops cause the uterus to shed its lining in a process termed menstruation. In the menstrual cycle, changes occur in the female reproductive system as well as other systems (which lead to breast tenderness or mood changes, for example). A woman's first menstruation is termed menarche, and occurs typically somewhere around age 12. The end of the reproductive phase of a woman is called the menopause, which occurs somewhere between the ages of 45 and 55. Medical problems such as anemia and infertility can be due to disorders of the menstrual cycle.
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Menstrual cycle Subcategories
Menstrual cycle Articles
Acne Vulgaris, the 8 Stages of Acne, Skin Care, Adult Acne, and Scar Removal Options. by Stephen Seabrook
Acne Vulgaris:
This is a medical term used to describe most cases of acne. It really isn't as bad as it sounds! Vulgaris doesn't mean that the acne is vulgar, only that it means that it is common.
Be aware that there a...
Learn to Love the Skin You're In by Alisa Vitti
Do You Qualify for an Extreme Make-Under?
Take our quiz to find out! 1) Do you pull at the skin on your face to give yourself an imaginary face-lift, smooth out wrinkles, and sharpen your jaw line? 2) Do you pinch the skin on your thighs,...
Alternative Ways to Relieve PMS by Simon Jones
Premenstrual syndrome (PMS) is a group of symptoms linked to the menstrual cycle. PMS symptoms occur in the week or two weeks before a womans menstruation. The symptoms usually go away after her period starts. PMS can affect menstruating women of any...
Pregnancy- Fertility by Elise Fisher
Can the old saying that the biological clock is ticking be true? In fact, there's truth in that adage. In the early childbearing years, women have a better chance of conceiving. There are many reasons for this.
A woman starts life with a fix...
IBS/IBD and Premenstrual Syndrome by Geraint Roberts
If you are a woman who may have been diagnosed with either irritable bowel syndrome or inflammatory bowel disease, you will probably be aware of a link between IBS/IBD and your menstrual cycle. Not every woman who suffers from irritable bowel syndrom...
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