Introduction: Menstrual cycle describes the female human reproductive cycle.
This is a cyclic endocrine regulated change in female anatomy and physiology that occur over 28 days during reproductive life between puberty and menopause.
The Menstrual cycle Definition
Definition: The cyclic events that rhythmically take place during the reproductive period of a women’s life are called the menstrual cycle.
Every month not only one but also two closely linked reproductive cycles take place Inside a woman’s body: they are
- Ovarian cycle
- Menstrual cycle
During the ovarian cycle: An egg matures inside one of the ovaries and is released into a fallopian tube, where it may be fertilized if sperms are present.
During the menstrual cycle: The endometrium thickens, converting the uterus into an incubation chamber where the fertilized egg can develop into a new human being.
If fertilization fails to occur, the lining of the uterus is shed through the vagina. This is called Menstruation.
Female Menstrual Cycle Hormones
The Female hormones in Women’s reproductive cycles are controlled by the “hypothalamus, pituitary gland, and the ovaries, these three releases the hormones that control the reproductive cycle,” hormones and functions.
Menstrual cycle safe days
Ovarian cycle and hormonal cycle are treated, as having a typical length of 28 days.
The ovarian cycle: when a girl is born, her ovaries contain around 2- 4 million immature eggs called Primary oocytes.
Each oocyte is surrounded by a layer of cells forming a container, which is the Primary follicle.
The ovarian cycle is controlled by two hormones released by the “pituitary gland, follicle-stimulating hormones, and luteinizing hormones and by gonadotropin-releasing hormones from the hypothalamus.”
What are the 4 stages of Menstrual cycle
The cycle can be described in three phases they are:
Stages of Menstrual cycle
Follicular phase this is(1-10) days
Ovulatory phase this is (10 – 14)
Luteal phase 14-28 days
What is Follicular Phase?
Follicular phase: In this phase, rising levels of GnRH from the hypothalamus stimulate the release of FSH and LH from the pituitary.
These menstrual hormones travel in the bloodstream to the ovaries, where they stimulate around 25 primary follicles to mature in the secondary follicles.
As the follicles enlarge, the ovaries release the hormones estrogen.
What is the Ovulatory Phase?
|Menstrual cycle Period Graph|
Ovulatory phase: (10- 14) In this phase, only one oocyte continued to mature. The mature follicle bulges out from the side of the ovary.
In the ovulatory phase, the estrogen level will be increased in the bloodstream feeds back to the pituitary gland, causing it to release large amounts of LH.
This causes the mature follicle to rupture and releases the mature egg into the fallopian, This is called ovulation.
Ovulation means the release of an egg from one of a women’s ovaries. After the egg is released, it travels down the fallopian tube, where fertilization by a sperm cell may occur.
Ovulation typically lasts one day occurs in the middle of a women’s cycle, about 2 weeks before she expects to get her period.
What is the Luteal Phase?
|Menstrual cycle Period Diagram|
Luteal Phase: once ovulation took, the ruptured matured follicles seal up and it becomes yellow body it is known as corpus luteum.
What is Corpus Luteum?
Corpus Luteum: This is a mass of cells that forms in an ovary and is responsible for the production of progesterone it occurs during early pregnancy.
Functions of Corpus Luteum
The role of corpus luteum depends on whether or not fertilization
- These corpus luteum secrets the second of the female sex hormones progesterone and some estrogen. Both of the menstrual hormones now suppress the release of FSH and LH by the pituitary gland
- If pregnant doesn’t occur, the corpus luteum degenerates, level of estrogen and progesterone decrease rapidly, the block on FSH and LH production is removed, and the next ovarian cycle begins
The menstrual cycle:
- The Menstrual cycle is the series of changes that the endometrium of the uterus goes through as it prepares to provide a protective environment in which a fertilized egg can settle and develop into a baby
- If a woman does not become pregnant during her cycle, the thickened layer of uterus Will be shed out and remains passing out of the vagina during menstruation.
- This Monthly bleeding is one of the few signs that a menstrual is taking place.
- The menstrual is controlled by changing levels of estrogen and progesterone released during the ovarian cycle.
|The Brain During the menstrual cycle / menstrual hormones|
What are the three-phase of the menstrual cycle
In the menstrual they again divided into three phases they are:
Different phases of the menstrual cycle
Menstrual phase (1-5) days
Proliferative phase (5-14)
Secretary phase (14-28)
Menstrual phase: The beginning of the cycle is marked by the menstrual periods or menstruation.
In this low level of progesterone produced by the ovaries, the endometrium will be constricted deprived of its blood supply, the walls start to fragment.
The menstrual flow of that passes out of the vagina from the uterus consists of tissues fragment and blood.
In this phase estrogen released by the ovaries stimulates the repair and growth of the endometrium so that it proliferates and becomes thicker and spongy.
On 14th day ovulation occur under the influence of LH.
Secretary Phase of Menstrual Cycle
|phase/ stages of the menstrual cycle|
Secretory phase endometrium
- After ovulation on the 14th day, the release of progesterone and estrogen from the ovaries corpus luteum stimulates the endometrium to develop further.
- The lining thickens Still more, and it’s blood supply increases.
- In this phase, it provides a fertilized egg with a receptive nutrient-rich environment in which to grow and develop.
Is secretory endometrium normal
- If fertilization doesn’t occur the corpus luteum breaks down, the endometrium starts to degenerates, and the cycle comes to an end.
- If fertilization occurs the corpus luteum receives the hormonal messages from the newly implanted embryo, which by preventing its regression, to continue production of the menstrual hormones and will keep the endometrium in place, it prevents menstruation and it maintains the pregnancy.
- Implanted embryo means implantation is the stage of pregnancy at which the embryo adheres to the wall of the uterus. The embryo receives oxygen and nutrition from the mother to be able to grow.
What are the 4 stages of the menstrual Phase