This Slide is based on the details of NCERT in class 12 CBSE. The topic contains all necessary events of Menstual Cycle.

2. The cycle of events starting from one menstruation till the next
one is called menstrual cycle.
It is the reproductive cycle in female primates, e.g monkeys,
apes, and human beings.
The cycle indicates a normal reproductive phase and extends
between menarch and menopause
One ovum is released during the middle of each menstrual
cycle.

3. Menarch-Menarche is the first menstrual cycle, or first
menstrual bleeding, in female humans.
Age of menarche is same that for puberty i.e 12 -13.
The timing of menarche is influenced by female biology, as
well as genetic and environmental factors,
especially nutritional factors.
It is often considered the central event of female puberty, as it
signals the possibility of fertility.

4. Menopause-The menopause is when a woman stops having
periods and is no longer able to get pregnant naturally.
or
It is the end of a woman's menstrual cycles.
 Periods usually start to become less frequent over a few months or
years before they stop altogether.
Sometimes they can stop suddenly.
A natural decline in reproductive hormones when a woman
reaches her 40s or 50s.

5. The menstrual cycle is
divided into four stages:
Menstrual phase
Follicular phase
Ovulatory phase
Luteal phase

6. The menstrual cycle is complex and controlled by many
different glands and the hormones that these glands
produce.
The cycle starts with menstrual phase, it lasts for about 3-5
days and involves the following event:
(a)If fertilization does not occur, the fertilized egg
undergoes “Autolysis”.
(b)Reduction of LH level causes regression of corpus
luteum by autolysis and thus a consequent fall in the
progesterone level in blood.

7. (c)The endometrial lining of
the uterus breaks down due to
the deficiency of progesterone
and is sloughed off.
Blood vessels rupture, causing
bleeding through vagina. The
process is called “menstruation
flow”. It occurs only when
ovum is not fertilized.

8. This phase also begins on the first day of menstruation, but
it lasts till the 13th day of the menstrual cycle.
The following events occur during this phase:
(a)The pituitary gland secretes a hormone that stimulates
the egg cells in the ovaries to grow.
(b)One of these egg cells begins to mature in a sac-like-
structure called follicle. It takes 13 days for the egg cell to
reach maturity.

9. ©While the egg cell
matures, its follicle
secretes a hormone
that stimulates the
uterus to develop a
lining of blood vessels
and soft tissue called
endometrium

10. On the 14th day of the cycle, the pituitary gland secretes a
hormone that causes the ovary to release the matured egg
cell.
The released egg cell is swept into the fallopian tube by the
cilia of the fimbriae.
During this phase both LH and FSH are at peak.
Rapid secretion of LH leading to its maximum level during
the mid cycle is called LH surge.

11. It induces rupture of
graafian follicle and thereby
the release of ovum i.e
ovulation.
The ovulation (ovulatory
phase ) is followed by Luteal
phase.

12. This phase begins on the 15th day and lasts till the end of
the cycle. The following events occur during this phase:
The egg cell released during the ovulation phase stays in
the fallopian tube for 24 hours.
The remaining parts of graffian follicle transform into the
corpus luteum.
The corpus luteum secretes large amounts of progesterone
essential to maintain endometrium.
The endometrium is necessary for implantation of
fertilized ovum and other events of pregnancy.

13. During pregnancy all events of menstrual cycles
stop and there is no menstruation .
In absence of fertiliation ,the corpus luteum
degenerates.
This causes disintegration of endometrium leading
to menstruation.

14. If a sperm cell does not
impregnate the egg cell within
that time, the egg cell
disintegrates.
The hormone that causes the
uterus to retain its
endometrium gets used up by
the end of the menstrual cycle.
This causes the menstrual
phase of the next cycle to
begin.

18. Follicle Stimulating Hormone (FSH) - released from the
pituitary gland in the brain, and stimulates the ovarian
follicles (fluid-filled sacs on the ovary containing an egg or
ovum) to mature.
Luteinizing Hormone (LH) -also released from the
pituitary gland in the brain at ovulation, and causes the
rupture of the mature ovarian follicle, releasing the egg.

19.  Estrogen - One of the female sex hormones
and often referred to as the ³growing
hormone² because of its role in the body.
Estrogen is responsible for growing and
maturing the uterine lining (lining that is
shed during menstruation) and also matures
the egg prior to ovulation. Estrogen is
produced mostly by the ovaries but also in
smaller amounts by the adrenal glands and in
fat tissue. It is most abundant in the first
half of the menstrual cycle (follicular phase).

20. Progesterone - Another of the female sex hormones.
It works in the body to balance the effects of estrogen and
is often referred to as the relaxing hormone.
Progesterone is produced after ovulation by the corpus
luteum (sack that the egg comes from) and dominates the
second half of the cycle (luteal phase).
Progesterone’s main job is to control the build up of the
uterine lining and help mature and maintain the uterine
lining if there is a pregnancy.
If there is no pregnancy, our progesterone levels fall and
the lining of the uterus is shed, beginning the menstrual
cycle.

21. Testosterone -An important sex hormone for both women
and men, although women have much lower levels.
Is produced by the ovaries and adrenal glands (right on
top of the kidneys), and has a surge at time of ovulation
and slight rise just before the menses.
Testosterone helps women maintain muscle mass and bone
strength, enhances sex drive and helps with overall sense of
well-being and zest for life.

22. On Day 1 of the menstrual cycle estrogen and
progesterone levels are low.
Low levels of estrogen and progesterone signal the pituitary gland
to produce Follicle Stimulating Hormone (FSH).
FSH begins the process of maturing a follicle (fluid-filled sac in the
ovary containing an egg).
The follicle produces more estrogen to prepare the uterus
for pregnancy
Eventson menstruation

23. At ovulation, usually around Day 12 – 14, increased
estrogen levels trigger a sharp rise in Luteinizing
Hormone (LH) from the pituitary gland, causing release
of the egg from the follicle.
The ruptured follicle (corpus luteum) now secretes
progesterone and estrogen to continue to prepare the
uterus for pregnancy. If the egg is not fertilized, estrogen
and progesterone levels drop and, on Day 28, the menses
begin.

24. During menopause, estrogen is no longer produced by the
ovaries and is made in smaller amounts by the adrenal
glands and in fat tissue. Estrogen is still produced in the
body, but in lower amounts than younger cycling women.
The most significant hormone change of menopause is the
lack of progesterone, so a time of estrogen dominance and
low progesterone.

25.  Queries????