Menstrual Cycle +2 Science

1. MENSTRUAL
CYCLE

2. Q. Write a note on
menstrual cycle.

3. INTRODUCTION
Human beings are most
evolved with well marked sexual
dimorphism. Puberty is the
maturity age marked by separate
male or female secondary sex
characters due to secretion of
respective sex hormones in gonads
guiding respective gametogeneeis.

4. INTRODUCTION cont…
A periodic menstrual cycle
occur in human female in
rhythmic intervals of 28 days
from puberty (12 to 13 years age)
to menopause (45 to 50 years age).

5. MENSTRUAL CYCLE
It is the periodic discharge of blood,
mucous and cellular debris from
uterine wall and ovum during
reproductive life of a female.
It occurs at an interval of 28 days.
It starts at onset of PUBERTY (12 to 13
year age) up to MENOPAUSE (45 to 50
year age).
It is absent during pregnancy.

6. OVARIAN FOLLICLE
Some cells of ovarian
germinal epithelium detach into
cortex. One of them undergo
oogenesis to become ovum and
rest surround it, the entire
structure is called as an ovarian
follicle and graffian follicle on
maturity.

7. STEPS OF MENSTRUAL CYCLE
 Menstrual phase – 1st to 5th days.
 Post menstrual / proliferation /
pre ovulation phase – 6th to 13th
days
 Ovulation phase – 14th day
 Postovulatory / premenstrual /
luteal / progesterone / secretory
phase – 15th to 28th day

8. EXTRA RELATED POINTS
 Hormonal Regulation of
Menstrual cycle
 Conclusion

9. MENSTRUAL PHASE
(1ST to 5TH Days)
This is the outflow of blood,
mucous and cellular debris from
uterine wall and ovum during
reproductive life of a female.
It is also called MENSTRUATION /
MENSEM MONTH.

10. POSTMENSTRUAL PHASE
(6TH to 13TH Days)
It is the period between end of
menstruation and onset of ovulation. In
this phase, ovarian follicles grow and
mature in side ovary.
They secrete hormone ESTROGENS. Under
influence of estrogens, uterine
endometrium is repaired.
Level of estrogens is maximum in this
phase. Contraction of uterus increases in
this phase.

11. OVULATION
(14TH Day)
Ovum is released into abdomen by
rupture of wall of grafian follicle
and ovary under the influence of
LUTEINIZING HORMONE.

12. POSTOVULATORY PHASE
(15TH to 28TH Days)
It is the period between end of
ovulation and onset of
menstruation.
Now cells of ruptured grafian
follicle become CORPUS LUTEUM.
It grows up to a week and secrete
hormone PROGESTERON.

13. POSTOVULATORY PHASE
(15TH to 28TH Days) cont…..
If ovum is not fertilised, it
degenerates into a white mass or
scar called CORPUS ALBICANS.
This is also called as LUTEAL PHASE
because, Corpus Luteum is formed
and functional only in this phase.

14. POSTOVULATORY PHASE
(15TH to 28TH Days) cont…..
This is also called as PROGESTERON
PHASE because, level of
progesterone is highest in this
phase.
This is also called as SECRETORY
PHASE because, uterine wall
secretes a nutritious fluid only in
this phase.

15. POSTOVULATORY PHASE
(15TH to 28TH Days) cont…..
This is also called as Progavid
phase because, during this, uterus
is prepared for pregnancy.

16. SIGNIFICANCE
Menstrual cycle marks the puberty
in female. On proper knowledge of
dates, probable date of copulation may
be decided for possible fertilisation,
pregnancy and baby birth by a couple.
Copulation must occur between
14th to 17th days of menstruation for
increased chance of fertilisation and
pregnancy.

17. HORMONAL
REGULATION

18. HYPOTHALAMUS
(BRAIN)
GONADOTROPIN
RELEASING FACTOR
PITUITARY GLAND

19. PITUITARY GLAND
FSH
(FOLLICLE
STIMULATING
HORMONE)
LH
(LUTEINIZING
HORMONE)

20. FSH LH
STIMULATES
DEVELOPMENT AND
MATURATION OF
OVARIAN FOLLICLES
FINAL MATURATION OF
FOLLICLES, OVULATION,
FORMATION OF CORPUS
LUTEUM
SECRETION OF
ESTROGEN FROM
FOLLICLES
SECRETION OF
PROGESTERON
Formation of uterine endometrium for pregnancy

21. Formation of uterine
endometrium for pregnancy
If fertilisation
occur by
copulation on
proper days
Pregnancy occur
NO MENSTRUATION
If fertilisation not
occur by copulation
on improper days or
no copulation
No pregnancy
MENSTRUATION OCCUR

22. CONCLUSION
The first menstruation in every
female is a risky day for her. This
should be properly guided by mother,
other female near and dear and
teachers, for safety of health and life of
female. Sanitary pads must be used by
females instead of dirty clothes during
menstruatiion and aware for it to
others for healthy life.