MENSTRUAL CYCLE

Professor

1. THE MENSTRUAL CYCLE
Presented By
John Britto Mary
Associate Professor

2. INTRODUCTION
When a female reaches pubertyshe usually has a
menstrual period every month.
The start of periods is known as menarche.
Menarchedoesn't happen until all the parts of a girl's
reproductive system have matured and are working
together.
This event occurs until the woman reaches
MENOPAUSE
Menopauseisthepermanentcessationofmenses.

3. Menstruationistheperiodicdischargeofbloodand
sloughedendometrium(collectivelycalledmensesor
menstrualflow)throughthevagina.
Menstruationoccursthroughoutawoman's
reproductivelifeintheabsenceofpregnancy.
TheaverageMenstrualCyclelengthis28days
(usualrange,about25to36days).
Averagedurationofmensesis5(±2)days.
Bloodlosspercycleaverages30ml(normalrange,
13to80ml)andisusuallygreatestonthe2ndday.
MENSTRUAL CYCLE

5. INTRODUCTION
This ‘period’ is apart of a cyclical process which
prepares the woman's body for the development of a
fertilized egg.
The process is controlled by several hormones.
What is a hormone?
A chemical substance produced by an endocrine
gland to coordinate one or more specific processes
in the body.

6. The process is controlled by several hormones.
GONADOTROPIN -RELEASING HORMONE (GnRH)
FOLLICLE STIMULATING HORMONE (FSH)
LEUTENIZING HORMONE (LH)
LUTEOTROPPIC HORMONE
OESTROGEN
PROGESTERONE

7. Each month, the ovary releases an egg cell. It
travels down the fallopian tube towards the uterus.

8. -TheeggmatureswhenFSHfromthe
pituitaryglandreachestheovary.
-Thematureeggissurroundedbya
fluidandajacketofcellsknownas
theGraafianfollicle.

9. Graafian Folllicle

10. OVULATION
The mature Graafian follicle moves toward the
surface of the ovary and ruptures releasing the
egg(ovum) from the follicle and the ovary.
This process, ovulation occurs about the 14
th
day
after the beginning of the menstrual period.
When the ovum is released it enters the oviduct and
passes along the oviduct to the uterus

11. After ovulation, the pituitary gland secretes lutenizing
hormone (LH).
LH changes the remains of the follicle into the
corpus luteum/yellow body.
Corpus luteum produces the hormone progesterone.
Progesterone further thickens the uterus lining and
increases blood supply

12. If fertilization does occur the corpus luteumenlarges
and continues to produce progesterone. The lining of
the uterus thickens and blood supply increases.
Progesteronealso causes the breast to enlarge.
These are pregnancy changes, progesterone is also
known as the ‘pregnancy hormone’.
Both oestrogenand progesterone slow down FSH
production when their concentrations become high.
Thus no more eggs develop.

13. If fertilization does not occur the corpus luteum
degenerates to ordinary ovary tissue and the
progesterone level falls.
The lining of the uterus breaks down and the egg
dies.
Lining along with blood passes out the vagina as the
menstrual period.
Cycle continues with increased FSH production and
egg development.
Cycle lasts approximately 28days

14. Normal Menstrual Cycle
What is the mean duration of the MC?
Mean 28 days (only 15% of ♀)
Range 21-35
What is the average duration of menses?
3-7 days
What is the normal estimated blood loss?
Approximately 30 ml
When does ovulation occur?
Usually day 14
36 hrs after the onset of mid-cycle LH surge

16. Hypothalamus
Pitutarygland
Follicle stimuating
hormone & LH
Maturation of
follicles
Estrogenhormone
Lining of the
uterus to thicken
Leutenizing
hormone
Results in
ovulation
stimulates
secrets
causes
Follicle releases
causes
Pitutary releases
Mature follicle burst
PATHOPHYSIOLOGY

17. Menstrual Cycle
TheMenstrualCyclecanbedividedinto3Phases.
-Follicular(Preovulatory)Phase
-OvulatoryPhase
-Luteal(Postovulatory)Phase

18. Follicular Phase
Day 1-13
Hypothalamus releases GnRF which stimulates release of LH and
FSH from Anterior Pituatary
Pituitary gland produces FSH
(Follicular Stimulating Hormone)
During this Phase ovary also
secretes increasing level of
Estrogen, to initiate
Endometrium
FSH act on ovary for prompt
development of several follicles (Each
Follicle Contains Egg)
During this phase one follicle
mature

19. Ovulatory Phase
Lasts for 14 to 36 hours
Phase begins when the level of LH surges.
LH stimulates dominant follicle to bulge
from the surface of ovary and finally
rupture, releasing the Egg.
Egg travel to Fallopian Tube. This is the
time when the women is most likely to
become Pregnant. The Egg can be
fertilized for only up to about 12 hours after
its release.

20. Luteal Phase, Day 15-28
After releasing Egg this empty Follicle develops the structure
called Corpus Luteum (CL)
CL secrets increasing amount of Progesterone. CL prepares Uterus
in case fertilization occurs.
Progesterone causes the Endometrium to thicken
If Egg is not FertilizedIf Egg is Fertilized
TheembryoproducesHumanChorionicGonadotropin
(hCG)whichwillbedetectedbyCLandthisHuman
ChorionicGonadotropinmaintainsCLandits
Progesteronesecretion.
The egg moves to the uterus and attaches itself to the
endometrium about six or seven days after ovulation,
where it begins to develop into a fetus.
CL destroys after 14 days
an new Menstrual Cycle
begins

22. MENSTRUAL DISORDERSMmenstrual
disorderENSTRUAL DISORDERS
Amenorrhea
Amenorrheaistheabsenceofamenstrualperiodin
awomanofreproductiveage.
PrimaryAmenorrhea
PrimaryAmenorrheaistheabsenceofmenstruation
inawomanbytheageof16.
SecondaryAmenorrhea
SecondaryAmenorrheaiswhereanestablished
menstruationhasceased—for3monthsinawoman
withahistoryofregularcyclicbleeding,or9months
inawomanwithahistoryofirregularperiods.
MENSTRUAL DISORDERS

23. Dysmenorrhea
Dysmenorrheaisagynecologicalmedicalcondition
characterizedbysevereuterinepainduring
menstruation.
Menorrhagia/Hypermenorrhea
Menorrhagiaisanunusuallyheavyandprolonged
menstrualperiodatregularintervals.
Abloodlossofgreaterthan80mlorlastinglongerthan7
daysconstitutesmenorrhagia
Hypomenorrhea
Hypomenorrheaisextremelylightmenstrualbloodflow
(scantyperiods).
MENSTRUAL DISORDERS

24. Metrorrhagia
Metrorrhagiaisuterinebleedingatfrequent,irregular
intervals,particularlybetweentheexpectedmenstrual
periods.
Menometrorrhagia
Menometrorrhagiaisaconditioninwhichprolongedor
excessiveuterinebleedingoccursirregularlyandmore
frequentlythannormal.
Polymenorrhea
Polymenorrheaisthemedicaltermforcycleswith
intervalsof21daysorfewer.
Oligomenorrhea
Oligomenorrheaisinfrequent(orverylight)menstruation.
Morestrictly,itismenstrualperiodsoccurringatintervals
ofgreaterthan35days.
MENSTRUAL DISORDERS

26. Thank You