Physiology of menstruation - Female Reproductive System - B.Pharm & Pharm.D - Menstrual Cycle

1. PHYSIOLOGY OF
MENSTRUATION
By- Dr.S.Kameshwaran

3. • Also known as menstrual cycle /menstruation
• It involves physiological changes occurring
periodically in females
• Menarche is the first menstruation which begins at
puberty
• Menopause is the phase when menstruation stops
permanently
• It occurs between 50-58 years of age
• However it may occur any time after the age of 42-
45 years
• The menstrual cycle is repeated at an average
interval of about 28/29 days
• During the middle of each menstrual cycle,
ovulation occurs – ovum is released during that
time.

4. PHASES OF MENSTRUAL CYCLE
MENSTRUAL PHASE - 1-5 Days
FOLLICULAR PHASE/ PROLIFERATIVE PHASE- 5-13 Days
OVULATION PHASE - 14th Day
LUTEAL PHASE/ SECRETORY PHASE - 15-28 Days

6. MENSTRUAL PHASE:
• This phase is characterized by vaginal bleeding
• Which is known as Menstruation/ menstrual bleeding/
menses/ Periods
• It occurs in the non pregnant women only
• Normal regular menstruation lasting for 3-5 (2-7) days is
known as EUMENORRHEA
• Menstruation results in the loss of 35 ml of blood (10-
80ml is normal)
• The endometrium linings shed up – which appears as a
mixture of tissue and blood
• PLASMIN an enzyme present in the endometrium inhibit
the blood clotting thus resulting in blood loss
• Due to this the women's should take more dietary iron
in their food
• Dysmenorrhea – painful uterine cramps during
menstruation

8. FOLLICULAR PHASE:
• In this phase the uterus lining become thick due
to increase in the estrogen level
• Due to the hormonal activity the development
of ovarian follicle is stimulated
• One or two formed follicle become dominant
the non dominant follicles die
• The dominant follicle mature further and secrete
more amount of estradiol (type of estrogen)
• Due to the estradiol a new endometrium layer
developed in the uterus – proliferative
endometrium

9. OVULATION PHASE:
• Matured egg produce the estradiol in big quantity so as
to trigger the Luteinizing Hormone release (LH)
• The LH starts secreting from 12th day of menstrual cycle
• The secretion will last for 48 hours
• The LH weakens the walls of ovarian follicles – they
become ruptured
• the matured ovum is released from the ovary
• Released ovum captured by fallopian tube
• The ova is travelling through the fallopian tube in order
to fertilized by sperm cells
• The size of the ovum is about 0.5mm in dia
• Some women experiencing characteristic pain during
ovulation – mittelschmerz (German term – middle pain)
• The pain last for two hours

10. LUTEAL PHASE:
• The corpus luteum is formed after ovulation
• The pituitary hormone converts the ruptured
residual follicle in to corpus luteum
• This corpus luteum is producing the estrogen and
progesterone for next 2 weeks
• The progesterone converts the proliferative
endometrium in to a secretory lining for
implantation and supporting the early pregnancy
• It also raises the body temperature by one- half to
one degree Fahrenheit
• If the egg is fertilized:
• Fertilized egg forms an early blastocyst passes
through the fallopian tube and implant itself in the
uterine cavity after 6-12 days of ovulation

12. • After the implantation the embryo’s existence will be
realized by the maternal system
• Initially the presence of human Chronic Gonadotropin (h
CG) in the urine
• This helps in the maintaining of corpus luteum and
production of testosterone from it
• In absence of Pregnancy:
• There is no h CG secretion
• The corpus luteum dies
• Declining the level of progesterone
• Due to the progesterone withdrawal menstrual bleeding
• Thus the base for begin the next cycle
• Raise in the FSH level to form a new follicles

13. THANK YOU