BIOLOGY FORM 5 CHAPTER 4 - 4.1D MENSTRUAL CYCLE

Secondary Sexual Characteristics
Menstrual Cycle

Menstrual Cycle
• 28 day cycle
• Starts at puberty (8-13 years)
• 1 secondary oocyte released every
month – alternating ovary
• Stops at menopause

• Every month the female body prepares for
pregnancy.
• This involves releasing an egg and making sure
the uterus is in perfect condition for
implantation.
• If pregnancy does not occur, the body will reset
and start the process again.
• This monthly cycle is called the menstrual cycle.
• It is controlled by hormones.

MENSES
Menstruation : Day 1-5
Menses is composed of:
•Blood from the ruptured capillaries
•Fragments of endometrial tissue
•Microscopic, atrophied, unfertilized ovum

During menses, Women may experience…
• Fluid retention (Bloating))
• Cramping
• Mood swings
• Weight gain
• Breast tenderness
• Diarrhea
• Constipation

MENSTRUATION & MENSTRUAL CYCLE
1 LO1: Students should be
able to describe what
is menstruation
2 LO2: Relate menstruation
with the menstrual cycle
3 LO3: State the hormones
involve in the menstrual
cycle
4 Assessment

is menstruation
cycle
4 Assessment
• What is menstruation?
The breakdown of uterine
lining (endometrium) that will
be discharge/shed through
the vagina with a small
amount of blood and some
cells
• When does it begin?
When a girl reaches puberty
(11 to 15 years)
• How long does this process
occur?
5 to 7 days

is menstruation
cycle
4 Assessment

Ovaries) 1
)Uterus lining (Endometrium) 2
During the menstrual cycle, changes occur in
:two parts of the body

Bleeding last for about 5 days

Ready for embryo
implantation

Egg travel to the upper part
of Fallopian tube

EMBRYO IMPLANT ITSELF ON THE
UTERINE LINING

WHAT IF THE EGG IS UNFERTILIZED?

is menstruation
cycle
4 Assesment

Inside the ovary
What happens in the ovary during the
menstrual cycle?
Day 1-13:
egg developing
inside the
growing follicle
Day 15-28:
empty follicle turns
into corpus luteum
(yellow body)
Day 14:
ovulation – egg
released from follicle
immature
eggs

CCyyccllee ooff FFoolllliiccllee DDeevveellooppmmeenntt
In the Ovary

HHoorrmmoonneess iinn tthhee
MMeennssttrruuaall CCyyccllee

The Menstrual Cycle
day cycle 28
Controlled by 4
:hormones
 FSH
 LH
 Oestrogen
 Progesterone
Pituitary
gland:
Releases
FSH & LH
Ovaries:
Release
oestrogen &
progesterone

Menstrual Cycle Hormones
Hormone Produced by Function
FSH Pituitary Stimulates growth
of follicles (ovary)
LH Pituitary Stimulates
ovulation
Oestrogen Ovaries
(follicles)
Repairs
endometrium
Progesterone Corpus
luteum
Thickening &
vascularity of
endometrium

)Menstruation (days 1-6
Changes in
the uterus
Changes in
the ovary
Follicles
immature
Uterus lining
(Endometrium)
breaks
Pituitary gland
releases FSH
: Changes in hormone levels

):Proliferation (days 6-13
Uterus
lining
repairs
: FSH causes
Follicles to develop
:Oestrogen
FSH causes
follicles to
develop
)Stops FSH (prevents more eggs developing
Starts LH release by pituitary gland
Uterus lining repair
Changes in
the ovary
Changes in
the uterus
Follicles
release
Oestrogen
Stimulated
by
oestrogen

):Ovulation (day 14
follicle
releases egg
Uterus
lining
remains
thick
Changes in
the ovary
Changes in
the uterus
:High LH level
High LH level
stimulates ovulation
Causes follicle to bust & release egg into oviduct

):Ovulation (day 15-24
Changes in
the ovary
corpus luteum
formed
Changes in
the uterus
:Progesterone
Releases
progesterone
Uterus lining
becomes
thicker & more
vascular
Causes the uterus lining to become more thicker & vascular

The Full Menstrual Cycle
menstruation proliferation
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Uterus lining
breaks
Ovary :Follicles
immature
:Ovary
Eggs begin to develop
Pituitary
gland
releases
FSH
Uterus lining
repairs
: FSH causes
New egg to develop
Oestrogen release
:Oestrogen
Stops FSH (prevents
)more eggs developing
Starts LH release
Uterus lining thickens
Uterus lining
remains thick
Ovary :Follicle
releases egg
:High LH level
Causes follicle
to bust &
release egg
into oviduct
But what
happens
after day
?14
Ovulation

Fertilisation - Yes
):pregnancy occurs(
Oestrogen and progesterone remain at
. high levels
, These hormones maintain the uterus lining
. No menstruation

Fertilisation - No
.Secondary oocyte dies
. Progesterone level drops
Uterus lining breaks
Menstruation starts
. Cycle continues

FSH
LH
Day 1 14 28
Growth of
follicle &
corpus luteum
Oestrogen
Progesterone
Uterus lining

is menstruation
cycle
4 Assessment
2 groups of hormone
Group 1
Control
changes in
the ovary
(development
of ovum)
Group 2
Control
changes in
the uterus
(thickening of
endometrium)

is menstruation
cycle
4 Assessment
•Follicle stimulating hormone
(FSH)
•Luteinising hormone (LH)

is menstruation
cycle
4 Assessment
• Oestrogen
•Progesteron

F.S.H
Made by…?
Causes
follicles to
grow.
Oestrogen
Made by…?
Causes uterus
lining to thicken.
START
HERE!
No pregnancy than P
stops and
menstruation starts.
Progesterone
Made by… L.H.
Made by…
Surge in this
causes ovulation.
If pregnant then O & P continue
to be produced to maintain the
uterus lining.

is menstruation
cycle
4 Assessment
For more assessment, click

Match the hormones with the right functions:
Stimulate growth of follicle in the ovary
Promotes repair and growth of the endometrium
lining
High levels inhibit FSH secretion and induce the
endometrium to thicken and vascularise
Causes ovulation to occur
Progesterone
LH
FSH
Oestrogen

What is the correct sequence?
End of assessment

TIMES
(DAY) IN THE OVARY IN THE UTERUS
1-5 Primary Follicle develop
6-13 Graafian Follicle matures
Menstruation occur
14 Endometrium Continues To
Thickens
15-24 Corpus Luteum develops
25-28 Endometrium begins to
breakdown
Corpus Luteum
degenerates if no
fertilisation
Endometrium become thicker.
Many blood vessel is develop
in it
Ovulation occurs
Endometrium repaires and
thickens

Premenstrual Syndrome
(PMS)
• Experienced by some women, hours to
days before menstruation, ends quickly
after menstruation begins

84
Menopause
• Occurs in the late 40s or the early 50s
• Menses stop
• Less production of oestrogens and progesterone
• Hot flashes and fatigue
• Migraine headaches, backaches and fatigue,
insomnia
• Mood swings
• Higher risk of osteoporosis

Common Complications of the
Female Reproductive System
 Ovarian Cysts- Fluid filled sacs on the surface of
an ovary usually harmless; sometimes more serious.
Symptoms include sudden severe abdominal pain,
fever, vomiting.
 Pelvic Inflammatory Disease- Infection leading
to damage of the reproductive organs. If untreated
may lead to chronic pain, infertility, and ectopic
pregnancy
 Breast Cancer- uncontrolled cell growth that
invades surrounding tissue and destroys it.

The uterine lining slowly
thickens from day 5 through
day 28

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

Breast Self Exams
Monthly check to detect changes that
could lead to breast cancer.
 Step One – “Look” In a mirror look for dimples,
puckering,redness of the breast skin, discharge from
the nipples, or change in breast size or shape.
 Step two – With flat fingers feel from top to bottom or
in circles making sure to examine the entire breast.

Follicle-stimulating
hormone (FSH) –
stimulate the formation
of several primary
follicles – only one of
which will eventually
develop while the other
disintegrate. Also FSH
stimulates the enzymes
that lead to the
formation of oestrogen.

Oestrogen produced
by modification of the
testosterone produced
by the follicle. It:
•Stimulates further
growth of the follicle
•Promotes repair of the
endometrium
•Inhibits secretion of
FSH

Development of
follicle within the
ovary is initiated by
FSH but continued by
LH. Eventually
becomes the corpus
luteum and inhibits
LH
The endometrium
thickens under the
influence of
oestrogen.

Luteinizing hormone
(LH) causes the release
of enzymes which
rupture the ovary wall
allowing the release of
the secondary oocyte.
After ovulation promotes
the transformation of the
follicle into the corpus
luteum.
Body temperature rises by
about 1oC at the time of
ovulation

Progesterone secreted
by corpus luteum:
•Prepares uterus wall
(endometrium) for
implantation of a
fertilised egg
•Promotes growth of the
mammary glands
•Inhibits FSH secretion

After ovulation the
endometrium becomes
thicker and highly
vascularized.

Menstruation is
initiated by falling levels
of oestrogen and
progesterone as the
corpus luteum
degenerates.

• The cycle starts with 6 days of menstruation
(the period).
• Then an increase in oestrogen causes the
lining to thicken.
OOeessttrrooggeenn
PPrrooggeesstteerroonnee
Speck-Made
http://commons.wikimedia.org/wiki/File:MenstrualCycle_en.svg

• An egg is released from an ovary at
approximately day 14 of the cycle.
• This is called ovulation.
• A sharp rise in oestrogen before day 14 causes
an increase in LH which causes ovulation.
Ovulation
OOeessttrrooggeenn
Speck-Made

• The uterus lining (endometrium) needs to be
thickest just after ovulation, so that it is ready
for a fertilised egg to implant.
OOeessttrrooggeenn
Speck-Made

• Progesterone then maintains the lining of the
uterus for approximately 10 days when
implantation can occur.
OOeessttrrooggeenn
Speck-Made

• The fall in progesterone trigger menstruation
and the cycle begins again.
OOeessttrrooggeenn
Speck-Made

Days 1-14
P i t u i t a r y
G l a n d
P r o d u c e s
F S H
F o llic le S t i m u la t in g H o r m o n e
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 it h i n t h e o v a r y
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 u t e r i n e l i n i n g t h i c k e n i n g

Days 14 - 28
P i t u i t a r y
G l a n d
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
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
P r o g e s t e r o n e
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

Secretes FSH –
starts the cycle
Pituitary gland

Secretes FSH –
starts the cycle
Pituitary gland
FSH causes the ovary to develop
an egg and release oestrogen

Pituitary gland
Oestrogen inhibits
production of FSH
Secretes FSH –
starts the cycle

Oestrogen inhibits
production of FSH
Secretes FSH –
starts the cycle
Lining of the uterus
thickens
Stimulates
release of LH
Pituitary gland

Oestrogen inhibits
production of FSH
Secretes FSH –
starts the cycle
thickens
Secretes LH
Stimulates
release of LH
Pituitary gland

Oestrogen inhibits
production of FSH
Secretes FSH –
starts the cycle
thickens
Secretes LH
Stimulates
release of LH
LH causes ovulation
and releases
progesterone
Pituitary gland

116
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Days
Days
1
LH
Follicular phase Ovulation Luteal phase
Estrogens
14
Estrogens
Progesterone
21 28
Progesterone
Menstruation Proliferative phase Secretory phase Menstruation
Ovarian events
Thickness
of endometrium
FSH
FSH LH
Ovarian activity
Uterine activity
7
1 3 5 9 13 15 17 19 21 23 25 27
7 1 3
Plasma hormonal
concentration
Plasma hormonal
concentration
Developing
follicle
Mature
follicle
Early
corpus luteum
Regressive
corpus luteum
Corpus
albicans
11

• Thus during oogenesis four cells are produced. Among
them one is functional ootid and three are non-functional
polar bodies. The ootid with very little change becomes an
ovum.

BIOLOGY FORM 5 CHAPTER 4 - 4.1D MENSTRUAL CYCLE

BIOLOGY FORM 5 CHAPTER 4 - 4.1D MENSTRUAL CYCLE

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