Menstrual Cycle

menstrual cycle The pattern of hormonal and physiologic changes that occur that occur in a woman's body in preparation for possible PREGNANCY. Though the average menstrual cycle spans 28 days, the frequency of MENSTRUATION varies widely among women and often within each woman individually. Menstrual cycles may be as short as 25 days or as long as 32 days and still be within the range of normal. Menstrual cycles outside these parameters may or may not be normal, depending on the woman's individual physiology and health status. The endocrine system directs the menstrual cycle.

Physiologic Phases of the Menstrual Cycle

There are four phases within the menstrual cycle that always occur in the same order:

1. The proliferative phase begins with the end of menstruation and the return of the endometrium (lining of the UTERUS) to its non-menstrual state and culminates with OVULATION about 14 days after the onset of menstruation. During proliferation the level of ESTROGENS in the BLOOD circulation rises and the level of PROGESTERONE drops. The changing hormone levels stimulate the maturation of up to 20 ova within their ovarian follicles, called ripening. The follicle containing the first ovum to reach

full maturity ruptures and releases the ovum into the fluid surrounding the fimbriae (fluted edges) of the fallopian tube. The other follicles that had started to develop then shrink; the ovary absorbs them and their ova.

2.  The expelled ovum leaves behind the corpus luteum, a structure of endocrine tissue that begins secreting estrogens and progesterone. This period of activity by the corpus luteum is the luteal phase, also called the secretory phase. The increased blood levels of the hormones cause the endometrium to thicken and its blood vessels to enlarge. The glands that line the endometrium increase their secretions, and the inner endometrium becomes spongy and engorged in preparation to support implantation should CONCEPTION occur. The luteal phase lasts about 10 days.

3.  When the ovum passes through the uterus without implanting, the corpus luteum involutes (turns in on itself) and the follicle absorbs it. The sudden drop in estrogens and progesterone causes the endometrial blood vessels to contract, called endometrial ischemia. The endometrial glands stop their secretions and the endometrium dramatically shrinks. This third phase of the menstrual cycle, called the ischemic phase, lasts 36 to 48 hours.

4.  The culminating phase of the menstrual cycle is menstruation, during which the anemic (blood-deprived) tissue of the endometrium sloughs away and passes from the body. The menstrual flow contains tissue fragments, endometrial secretions, and blood. Menstruation lasts 3 to 5 days in 85 percent of women; about 15 percent of women menstruate for 7 days. Though menstruation is the last phase of the menstrual cycle, doctors consider the first day of menstrual bleeding to be the start of the menstrual cycle.

Endocrine Regulation of the Menstrual Cycle

The HYPOTHALAMUS, PITUITARY GLAND, and corpus luteum regulate the menstrual cycle. The hypo-thalamus initiates the proliferative phase of the menstrual cycle by releasing GONADOTROPIN-RELEAS-ING HORMONE (GNRH). GnRH stimulates the pituitary gland to secrete a surge of FOLLICLE-STIMULATING

hormone (fsh), which induces an ovarian follicle to begin secreting estrogens. The estrogens cause the ovum within the follicle to begin ripening. The rising level of estrogens in the blood circulation triggers the hypothalamus to again release GnRH, which this time stimulates the pituitary gland to secrete luteinizing hormone (lh). LH causes the ovarian follicle to produce progesterone, which brings the ovum to maturity and release (ovula-tion). Without pregnancy the blood levels of estrogens and progesterone both fall and menstruation takes place.

Disturbances of the Menstrual Cycle

Numerous factors may disrupt the menstrual cycle, the most common being pregnancy. When a fertilized ovum (zygote) implants in the endometrium, the menstrual cycle ends and pregnancy begins. The menstrual cycle does not return until six to eight weeks (and sometimes longer, up to months in women who are breastfeeding) after childbirth. Hormonal imbalances may also disrupt the menstrual cycle. Hypothyroidism (underactive thyroid gland) or hyperthyroidism (overactive thyroid gland) is a common source of such hormonal disruption. Disorders of the pituitary gland, such as pituitary adenoma, or the adrenal glands, such as adrenal insufficiency, often alter the body's endocrine matrix in ways that affect the menstrual cycle.

Numerous medications and treatments such as chemotherapy and radiation therapy may affect ovarian function. Menstrual disturbances may occur as a result of underlying health conditions such as polycystic ovary syndrome (pcos), obesity, anorexia, and extreme emotional or physical stress. Though a normal menstrual cycle often occurs with a single functioning ovary, the absence or loss of both ovaries ends the menstrual cycle. Oophorectomy is the surgical operation to remove an ovary. Women who participate in intense athletic activities, such as marathons and triathlons, may have irregular menstrual cycles or amenorrhea (absence of menstruation).

For further discussion of the menstrual cycle within the context of the structures and functions of reproduction and sexuality, please see the overview section "The Reproductive System." For further discussion of the menstrual cycle within

the context of the structures and functions of the endocrine system, please see the overview section "The Endocrine System."


Bronchial asthma Linked To Menstrual period; Bodily hormones Affect Respiratory Signs and symptoms In Ladies.

Reblogged through someone someplace: A brand new study shows that a moms menstrual cycle can impact respiratory signs and symptoms, possibly exacerbating problems…
Knowing the menstrual period being a saw to alter your daily life

… associated with my body could be the menstrual period. I recall being baffled… realize more reasons for the menstrual period. We wished which i got…
Also How The Menstrual period has Changed!

Also How The Menstrual period has Changed! Aug 25, 2010 second … which have transformed. The entire idea of the menstrual period has evolved as well. Till…
Abnormal Menstrual Cycles and also Perimenopause

… from the first indicators that warn from the presence associated with menopause could be the improvement in menstrual series. For several women create their less normal menstrual series, Other people…
Can rheumatoid arthritis pain follow my menstrual cycle?...

Contact your Doctor And also talk to your pet. Because We don’t number You might have L. A We have Este. The. But check out or contact. Indeed, you might be correct, not just variations, but additionally chemical ersus

How can i figure out who many days my menstrual cycle is?...

because u just got ur first time period.. we wouldnt even attempt to figure it because after i had the first one they might be disseminate between 2-3 weeks with regard to

What do you think about the menstrual cycle?...

For me personally individually, it’s not an enormous offer. The cramping the first one 5 times are no enjoyable, however they do disappear ultimately. I believe the most severe part is simply feeling such as con

How safe it's to ejaculate inside on the first day after menstrual cycle?...

That it is never secure.. Hmm.

Simply use a weakling condom! Right i’d say approximately about 90% however that doesn’t prevent STD’s or HELPS. you are able to toss from the entire of your life more than a good

How did early humans deal with their menstrual cycle?...

great issue. idk. They frequently simply utilized rags, therefore one of the numerous expression for periods which have continued. Actually in those situations, ladies RARELY got

Can Depo Provera completely change your menstrual cycle?...

The actual depo should really offer you only four periods annually. Modifying methods can toss your body directly into upheaval for some time, however that is a good abnormally any period of time.

Can certainly Menstrual Periods (How to manage the Circulation! ): J-Wro Lo-Lo Vegetarian Videos

Stick to J-Wro on these websites (scroll lower for more information with this video): — Sign up for my video clips: — Web site: — Superfoods — Food blender www.blendtec.c

Monthly Cramps: What can cause this?

Cartoon video demonstrating exactly how menstruation happens and exactly how this usually leads to unpleasant menstrual cramping

GEEZ, she’s on her behalf MENSTRUAL PERIOD!!!

Among the most difficult, yet required, conversations you need with all the girl if you’re dating is growing rapidly, “When is actually her period arriving? ” You should know the girl period!!! Don’t allow “Bad Young man Red” hunt an individual! D

Aasai Nayagi — Doctor Explains Regarding Menstrual period

To get more full size tamil movies youtube . com. com To get more full size malayalam movies youtube . com. com To get more full size telugu movies youtube . com. com To get more full size kannada movies youtube . com. com Enjoy w tamtym miejscu

Knowing your own menstrual period

… Within an interview in the association' ersus office upon Oxford Road, Port-of-Spain, Maynard explained that nearly all women don’t realize their own menstrual period. “Not most people have the 28-day cycle as well as if you carry out, sometimes it could be disrupted by, tension

Wallet Way of life: Menstrual period

Aids you manage information regarding your menstrual period helping you attract conclusions with regards to your cycle and also male fertility.

Physical exercise and the Menstrual period [VHS]#@@#@!!

The fundamental endocrinology from the female menstrual period and also the hormonal adjustments that can happen with strenuous workout teaching. Additionally deals with physiol

LilyBeth Golfing Women’s Published Butterfly Tee Owner Baseball glove (Medium, Left)

Perfect for serious ladies golf players, LilyBeth’s traditional Tee Glove provides fit, functionality and style. Featuring colourful designs, this particular practical glove maintain

Have a Regulated Menstrual period Along with Dianette

… e the huge interest in the junk birth control tablets, medicine producers have been motivated to create new versions of medicines of this course under different brands. The variety of contraceptive tablet users in the united kingdom just is assumed to become greater than 4. 5 mil which is smag…