The Menstrual Cycle

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The menstrual cycle is a cycle of physiological changes that can occur in fertile females. Overt menstruation (where there is blood flow from the uterus through the vagina) occurs primarily in humans and close evolutionary relatives such as chimpanzees. Females of other species of placental mammal undergo 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, under the control of the endocrine system, is necessary for reproduction. It is commonly divided into three phases: the follicular phase, ovulation, and the luteal phase; although some sources use a different set of phases: menstruation, proliferative phase, and secretory phase. The length of each phase varies from woman to woman and cycle to cycle, though the average menstrual cycle is 28 days. Menstrual cycles are counted from the first day of menstrual bleeding. Hormonal contraception interferes with the normal hormonal changes with the aim of preventing reproduction.
Stimulated by gradually increasing amounts of estrogen in the follicular phase, menses slow then stop, and 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). Approximately mid-cycle, 2436 hours after the Luteinizing Hormone (LH) surges, the dominant follicle releases an ovum, or egg in an event called ovulation. After ovulation, the egg only lives for 24 hours or less without fertilization while 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 around age 12. The end of a woman's reproductive phase is called the menopause, which commonly occurs somewhere between the ages of 45 and 55.

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[daleena19]

WOW! Thanks for this great elaboration! Big exam on this tomorrow and the book just gave me a headache! Thank you!

[yasser476]

you skipped a phase

[sammy98244]

Great Video KEEP IT UP I've been using HOME CHECK OVULATION TEST KIT for a long time and I still get butterflies when that little smiley shows his face. :) I got one from the internet by searching on Google HOME CHECK OVULATION KIT it was great!

[samuel146]

can someone help me please what are the uterine tissues

[LaurenHPNo1Fan]

@yasser476

Pause at 2.30 and you'll see it.

[007jacca]

@lolaxian so what????

[lolaxian]

@monika3191 no actually it is genetic lmao, i use to live in dubai and there were may indians who had that problem. search it online, they pronounce it w instead

[monika3191]

@lolaxian That's totally racist.

[lolaxian]

the narattor is indian. he cant pronounce the "v" properly

[to0os]

Great , so helpful

thanx alot :)

[Mikkelkid111]

LÅLÅLÅLÅLÅ HENRIK FALKENBERG <33333333333

DU MIN GUD!