The menstrual cycle involves cyclic changes in the ovaries and uterus that occur approximately every 28 days in females. It includes the thickening of the uterine lining under the influence of estrogen and progesterone. Around day 14, a spike in LH triggers ovulation and progesterone production. If fertilization does not occur, progesterone levels fall and menstruation begins as the uterine lining sheds. This cycle is governed by hormones from the pituitary gland and ovaries.

1. MENSTRUAL CYCLE
PREPARED BY
Mrs.S.SAVITHRI DEVI
KV NO.1 CPCRI KASARAGOD

2. Menstrual cycle:-
 The cyclic changes that occur in the
reproductive organs of primate
females(monkeys, apes , human beings
, constitute the menstrual cycle).
 The cycle of events starts from one
menstruation till the onset of the next
and lasts for about 28 or 29 days(a
mensem, means a month).

3.  The peculiar feature of this cycle is the
periodic vaginal bleeding called
menstruation which lasts for about
3-5 days.
 The menstruation in human female
begins at puberty and is called
menarche.
 In females successive cycles may vary
in length by 1-2 days.
 It is absent during pregnancy, may be
suppressed during lactation and
permanantely stops at menopause

4. What is the menstrual cycle?
 The process in which females ripen or
release one mature egg.
 The average menstrual cycle will repeat
itself about every 28 days, but normal
menstrual cycles can range from 21 to 40
days.
 The menstrual cycle is the regular natural
change that occurs in the female
reproductive system (specifically the
uterus and ovaries).
 The cycle is required for the production of
oocytes,and for the preparation of the
uterus for pregnancy.

5.  Up to 80% of woman report having
some symptoms during the one to two
weeks prior to menstruation.
 Common symptoms include ace, tender
breasts, bloating, feeling tired, irritability
and mood changes. These symptoms
interfere in normal life.
 The first period usually begins between
twelve and fifteen years of age, a point
of time known as menarche.
 They may occasionally start as early as
eight, and this onset may still be
normal.

6.  Next period may occur in 21-45 days in
young women and 21-35 days in adults.
 The menstrual cycle is governed by
hormonal changes.
 This changes can be altered by using
hormonal birth control to prevent
pregnancy.
 Each cycle can be divided into three
phases based on events in the ovary or
in the uterus.

7.  The ovarian cycle consists of the
follicular phase, ovulation and luteal
phase.
 The uterine cycle is divided into
menstruation, proliferative phase, and
secretory phase.

10. Changes in Pituitary
Hormones Days 1-14:
 During the first half of the cycle (Days 1-
14) the pituitary produces FSH, which
stimulates egg production.
 This hormone also triggers the release
of estrogen from the ovaries.

11. Changes in Pituitary Hormones
Days 14-28:
 On the 14th day the pituitary begins releasing
LH causing ovulation.
 LH also directs the production of
progesterone which maintains the growth of
the endometrium.
 If the egg is not fertilized upon arrival in the
uterus progesterone levels drop causing
estrogen levels to drop leading to
menstruation.

12. Pituitary Hormones

13. Changes in the Ovaries:
Stage 1 - ovum
begins to develop.
Stage 2 - egg continues
to ripen; follicle growth
Stage 3 - Ovulation
fully mature egg
bursts out of follicle.
Stage 4 - Egg enters fallopian tube follicle
remains and forms the corpus luteum.

14. Changes in the Ovaries:
 Stage 1 - An egg is beginning to mature
within a cluster of cells called a follicle
 Stage 2 - Rapid follicle and egg growth
 Stage 3 - Ovulation occurs; fully mature egg
bursts out of the follicle (fertile) empty follicle
transforms into the corpus luteum
 Stage 4 - Egg travels through fallopian tube
(7 days) if not fertilized upon arrival in uterus
the corpus luteum shrinks triggering
menstruation and ripening of new egg.

15. Changes in Ovarian
Hormones:
 Estrogen -gradually increases during days
1-14; signals body to thicken the lining of the
uterus. Levels drop sharply after ovulation.
 Progesterone -Levels remain low during the
first half of the cycle and then increase
sharplyduring the second half of the cycle.
Maintaining the growth of the endometrium
lining.

16. Changes in the Uterus:
Stage 1- Day 1-5
menstruation
Stage 2 Day 5- 13
pre-ovulatory stage Stage 3 Day 14
Ovulation
Stage 4 Day 15-28
post-ovulatory
stage

17. The uterine lining slowly thickens
from day 5 through day 28

18. Changes in the Uterus:
 Stage 1- Menstruation- Endometrium
breaks down and blood, mucus, tissue,
and the egg are shed through the
vagina.
 Stage 2- Menstrual flow stops &
endometrium begins to thicken.
 Stage 3- Endometrium continues to
thicken.
 Stage 4- The endometrium is at it’s
thickest point.

19. Ovarian Hormones

20. Days 1-14
T r i g g e r s u t e r i n e l i n i n g t h i c k e n i n g
P r o d u c e s
E s t r o g e n & O v u m
T r i g g e r s f o r m a t i o n o f t h e
F o l l i c l e
W i t h i n t h e o v a r y
P r o d u c e s
F S H
F o l l i c l e S t i m u la t i n g H o r m o n e
P i t u i t a r y
G l a n d

21. Days 14 - 28
C o n t i n u e s u t e r i n e l i n i n g t h i c k e n i n g
P r o d u c e s
P r o g e s t e r o n e
T r i g g e r s O v u l a t i o n
a n d t h e f o r m a t i o n o f t h e
C o r p u s L u t i u m
W i t h i n t h e o v a r y
P r o d u c e s
L H
L u t i n i z i n g H o r m o n e
P i t u i t a r y
G l a n d