1. The menstrual cycle is controlled by hormones from the pituitary gland and ovaries. 2. At the start of the cycle, FSH causes a follicle to mature and estrogen levels rise. 3. Around day 14, a LH surge causes ovulation, and the follicle becomes the corpus luteum which produces progesterone. 4. Towards the end of the cycle, the corpus luteum breaks down leading to menstruation as estrogen and progesterone levels fall.

1. PHYSIOLOGY OF
MENSTRUATION AND
HORMONAL CONTROL
By:M.K.Saboi (Mrs.)

2. PHYSIOLOGY OF MENSTRUATION
Menstruation is affected by the following:
1. Sudden reduction in the level of progesterone
and oestrogen because corpus luteum has
degenerated.
12/22/2022
Mrs Mirriam Saboi
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3. PHYSIOLOGY OF MENSTRUATION
CONT’D
 The progesterone exerts negative feedback
effect on the hypothalamus and pituitary gland
leading to FSH and LH levels to fall.
 Decreased stimulation of the endometrial cells
by the two hormones leads to breakdown of
the endometrium.
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Mrs Mirriam Saboi
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4. PHYSIOLOGY OF MENSTRUATION
CONT’D
2. There is rapid involution of the endometrium to
about 65% of its thickness
3. During 24 hours preceeding to onset of bleeding
the spiral blood vessels leading to endometrial
mucosa to go into spasms probably due to
effects of involution.
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Mrs Mirriam Saboi
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5. PHYSIOLOGY OF MENSTRUATION
CONT’D
The distal areas beyond the constriction become
necrotic and slough off or shed due to lack of
blood supply.
The endometrium is shed up to the basal layer
along with blood from the capillaries.
The uterine contractions help in expelling
menstrual flow.
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Mrs Mirriam Saboi
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6. MENSTRUAL FLOW (MENSES)
This is a monthly vaginal bleeding. It consists of:
1. Blood from disrupted blood vessels amounting
to 30ml (ranging from 10-80ml)
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Mrs Mirriam Saboi
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7. MENSTRUAL FLOW (MENSES) CONT’D
2. Addition 35ml of serous fluid
3. Necrotic sloughs of tissue from functional layer
4. Fibrinogens prevent menses from clotting unless
menses are in excess.
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Mrs Mirriam Saboi
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8. SUMMARY OF MENSTRUAL CYCLE
1. The menstrual cycle is a recurring cycle lasting
approximately 28 days though this vary
according to each individual woman.
 The gonadotrophin hormone from the pituitary
hormone causes the graafian follicle to mature
and large quantities of oestrogen to be
released.
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Mrs Mirriam Saboi
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9. SUMMARY OF MENSTRUAL CYCLE
CONT’D
2. On about 3rd day after the start of last menstrual
flow this oestrogen causes the endometrium to
be regenerative again and proliferation then
takes place.
3. On approximately the 14th day there is a surge
of LH causing one of this follicles to rupture due
to relaxin hormone and ovulation to take
place.
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Mrs Mirriam Saboi
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10. SUMMARY OF MENSTRUAL CYCLE
CONT’D
4. The ruptured follicle then develops into the
corpus luteum.
This secretes large quantities of progesterone
with eostrogen in lesser amounts. Progestrone
act upon the proliferative endometrium causing
increased vascularity and glandular tissue
formation.
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Mrs Mirriam Saboi
10

11. SUMMARY OF MENSTRUAL CYCLE
CONT’D
5. Towards the end of 14 days the corpus luteum
degenerates, the levels of oestrogen and
progesterone decrease greatly and menstruation
takes place.
At this time the endometrium with the
unfertilized ovum is shed.
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Mrs Mirriam Saboi
11

12. SUMMARY OF MENSTRUAL CYCLE
CONT’D
6. The discarding of highly vascular endometrium
causes bleeding.
This bleeding can last for 3-7 days with an
average of 5 days.
The average amount of desquamated tissue,
blood and serous fluid is about 50-60ml.
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Mrs Mirriam Saboi
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13. HORMONAL CONTROL
The anterior pituitary gland under the control of
the hypothalamus and the ovary are the glands
responsible during the menstrual cycle.
1. Anterior Pituitary gland secretes the following
hormones
(i) FSH which ripens the graafian follicle
(ii) LH maintains corpus luteum
(iii) Prolactin hormone begins early preparation of
the breast for the breast to produce milk. 12/22/2022
Mrs Mirriam Saboi
13

14. HORMONAL CONTROL CONT’D
2. The ovary secretes the following hormones
(i) Oestrogen which is essential for the
development of female characteristics and it
produces regrowth of endometrium
(ii) Progesterone stimulate necessary physiological
preparation for pregnancy
(iii) Relaxin hormone ripens the graafian follicle
and allows it to rupture.
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Mrs Mirriam Saboi
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15. FUNCTIONS AND EFFECTS OF
OESTROGEN
Oestrogen is produced by the graafian follicle
and corpus luteum.
It comprises of a number of compounds
including; oestradoil and oestrone while oestriol
is excreted in urine.
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Mrs Mirriam Saboi
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16. FUNCTIONS AND EFFECTS OF
OESTROGEN CONT’D
The most important of the 3 is oestradoil.
The principle function of the oestrogen hormone
is to cause cellular proliferation and growth of
sexual organs and other tissues related to
reproduction e.g breast tissue.
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Mrs Mirriam Saboi
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17. EFFECTS OF OESTROGEN
The effects are widespread but we shall mention
only a few.
1. It is responsible for sexual secondary
characteristics e.g growth of sexual organs at
puberty.
 At this time oestrogen is secreted about 20
times more than in childhood.
 At puberty there is an increase in size of
uterus, vagina and uterine tubes. 12/22/2022
Mrs Mirriam Saboi
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18. EFFECTS OF OESTROGEN CONT’D
2. The uterus apart from increasing in size its
lining the endometrium proliferates and secretes
Mucin in preparation for embedding of fertilized
ovum.
3. There are changes in the vaginal epithelium
from cuboidal into stratified which are more
strong to trauma and infection.
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Mrs Mirriam Saboi
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19. EFFECTS OF OESTROGEN CONT’D
It also influences the production of cervical
mucus into the vagina, this in turn encourages
the growth of dodelein bacilli which produces
lactic acid and renders the vagina to be acidic.
4. It causes the number of ciliated epithelial cells
and their activity to increase which help to
propel the fertilized ovum towards the uterus.
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Mrs Mirriam Saboi
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20. EFFECTS OF OESTROGEN CONT’D
5. It increases the length of the long bones and
close the epiphyses.
6. Positive feedback, a day immediately before
ovulation a surge of FSH and LH set a positive
feedback of oestrogen.
7. It is associated with retention of electrolytes and
fluids in body tissues, therefore it inhibits FSH
and encourages fluid retention
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Mrs Mirriam Saboi
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21. PROGESTERONE
This is an ovarian hormone produced by the
corpus luteum under the influence of LH.
Progesterone only acts on tissues that have
been previously acted upon by oestrogen.
Progesterone is the most important progestin
produced.
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Mrs Mirriam Saboi
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22. FUNCTIONS OF PROGESTERONE
The most important function is to produce
functional changes in the endometrium for the
development of tortuous glands and a rich
supply of blood in preparation for anticipated
fertilized ovum.
Other effects are:
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Mrs Mirriam Saboi
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23. FUNCTIONS OF PROGESTERONE
CONT’D
1. Causes the temperature to rise by 0.5 degrees
Celsius when ovulation has taken place.
2. Give rise to tingling and fullness of breast prior
to menstruation
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Mrs Mirriam Saboi
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24. FUNCTIONS OF PROGESTERONE
CONT’D
3. In pregnancy progesterone decreases frequency
of uterine contractions thereby helping to
prevent expulsion of the implanted ovum.
It relaxes tone of smooth muscles throughout
the body.
4. Promotes secretory changes in the fallopian
tube to provide nutrition to the dividing ovum as
it travels towards the uterus.
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Mrs Mirriam Saboi
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25. FUNCTIONS OF PROGESTERONE
CONT’D
5. It is responsible for the development of lobules
and alveoli in the breast which become
enlarged, swell and secretory in nature.
6. It increases water and sodium retention in
body tissues.
7. Negative feedback –progesterone and
oestrogen are responsible for negative feedback
for FSH and LH in the half of the cycle.
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Mrs Mirriam Saboi
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26. RELAXIN HORMONE
Its maximum level is reached during pregnancy
between 38 and 42 weeks.
It is produced in the ovary by the graafian
follicle and also by the placenta during
pregnancy.
Its effects are:
(i) Relaxes the pelvic girdle
(ii) Softens the cervix
(iii) Suppresses uterine contractions
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Mrs Mirriam Saboi
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27. INHIBIN HORMONE
It is also produced by the corpus luteum and inhibits
the production of LH and probably FSH as well.
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Mrs Mirriam Saboi
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28. PUBERTY
Puberty means the onset of adult sexual life.
It is the period in life during which the
reproductive organs undergo great development
and reach maturity to be able to reproduce.
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Mrs Mirriam Saboi
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29. PUBERTY CONT’D
It begins at the age of 8 years and usually
culminating in onset of menstruation between
ages 11-16 years.
It is caused by effects of gradually increase of
gonadotrophin hormone especially FSH by the
anterior pituitary gland.
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Mrs Mirriam Saboi
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30. PUBERTY CONT’D
SIGNS OF PUBERTY
Breast development
Appearance of pubic hair
Considerable growth of body and acquires a
certain shape of wide hips and narrow
shoulders.
Beginning of menstruation (menarche)
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Mrs Mirriam Saboi
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31. MENOPAUSE
This is the period during which menstrual cycle
ceases and female sexual hormones diminishes
rapidly.
It is the end of reproduction life.
During a few months or years preceeding to
menopause at approximately 40-50 years the
periods becomes irregular and ovulation fails to
occur in some of the cycles.
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Mrs Mirriam Saboi
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32. MENOPAUSE CONT’D
This is the period known as Climacteric. The
age is between 45-50 years.
2 years should elapse since last period before
concluding that menopause has taken place.
Within those two years a woman should
continue taking contraceptive method otherwise
she may fall pregnant.
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Mrs Mirriam Saboi
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33. MENOPAUSE CONT’D
SIGNS OF MENOPAUSE
Hot flashes
Mood swings
Irritability
Increased tendency to obesity
Signs of aging like geriatric tendencies while
some end up as psychiatric patients.
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Mrs Mirriam Saboi
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34. MENOPAUSE CONT’D
These signs are due to fall in oestrogen level
because the ovary has run out of graafian follicle to
secrete oestrogen and no longer respond to pituitary
stimulation.
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Mrs Mirriam Saboi
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35. THE END
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Mrs Mirriam Saboi
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