The document discusses normal menstruation, including: 1) Menstruation is the shedding of the endometrium due to declining estrogen and progesterone levels caused by the regression of the corpus luteum. 2) The hypothalamic-pituitary-ovarian axis regulates the menstrual cycle through hormones like GnRH, FSH, LH, estrogen and progesterone. 3) A normal menstrual cycle is 28 days, with bleeding typically lasting 3-7 days.

1. Normal menstruationNormal menstruation
Menstruation is the cyclic bleeding caused by shedding of theMenstruation is the cyclic bleeding caused by shedding of the
secretary endometrium due to decline in estrogen andsecretary endometrium due to decline in estrogen and
progesterone cause by regression of the corpus luteum .progesterone cause by regression of the corpus luteum .
This depends mainly on the functional integrity of threeThis depends mainly on the functional integrity of three
endocrine sources :-endocrine sources :-
1- the hypothalamus1- the hypothalamus
2- the anterior pituitary gland2- the anterior pituitary gland
3- the theca granulosa cells of the ovary3- the theca granulosa cells of the ovary
This often referred to as the hypothalamic – pituitary ovarianThis often referred to as the hypothalamic – pituitary ovarian
axis .axis .
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2. A neuro chemical transmitter known as gonadotropinA neuro chemical transmitter known as gonadotropin
releasing hormone (GnRH) which produced in thereleasing hormone (GnRH) which produced in the
hypothalamus is liberated in a pulsatile fashion into thehypothalamus is liberated in a pulsatile fashion into the
capillary plexus of the median eminence and is carriedcapillary plexus of the median eminence and is carried
through the portal vessels to the anterior lobe of thethrough the portal vessels to the anterior lobe of the
pituitary gland .the result of its neuro hormonal action ispituitary gland .the result of its neuro hormonal action is
the production and release of the gonadotrophins FSHthe production and release of the gonadotrophins FSH
and LH from the anterior pituitary cells , these hormonesand LH from the anterior pituitary cells , these hormones
are transmitted to the ovary where they stimulate follicleare transmitted to the ovary where they stimulate follicle
development and ovulation .development and ovulation .
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3. Ovarian cycle :-Ovarian cycle :-
 At the time menstruation is taking placeAt the time menstruation is taking place growthgrowth of a number ofof a number of (100 -1000)(100 -1000)
primordial ovarian follicles in both ovaries is stimulated by FSH and toprimordial ovarian follicles in both ovaries is stimulated by FSH and to
a lesser extend by LH and continue for 5 to 7 days this is calleda lesser extend by LH and continue for 5 to 7 days this is called
recruitment .recruitment .
Selection :Selection :
 Only one follicle is selected to reach maturity to form the graafianOnly one follicle is selected to reach maturity to form the graafian
follicle .follicle .
 production of estradiol resulting from the increase of both FSHproduction of estradiol resulting from the increase of both FSH
receptors and granulosa cells is responsible for this process ofreceptors and granulosa cells is responsible for this process of
selectionselection
Dominance :Dominance :
TheThe selected follicle ultimately becomes the dominant follicle over theselected follicle ultimately becomes the dominant follicle over the
next 5 days to form the graafian follicle by suppressing the growth ofnext 5 days to form the graafian follicle by suppressing the growth of
the remaining follicles by secreting sufficient estradiol and inhibin tothe remaining follicles by secreting sufficient estradiol and inhibin to
suppress pituitary FSH .suppress pituitary FSH .
1- follicular phase :-
Recruitment :
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4. The graafian follicle :The graafian follicle :
 at the end of maturationat the end of maturation
the graafian follicle isthe graafian follicle is
about 18-25 mm inabout 18-25 mm in
diameter and consists of :diameter and consists of :
- OvumOvum
- Zona pellucidaZona pellucida
- Corona radiataCorona radiata
- Cumulus oophorusCumulus oophorus
- Perivitelline spacePerivitelline space
- Cavity filled with liquorCavity filled with liquor
folliculifolliculi
- Granulosa cellsGranulosa cells
- Theca cellsTheca cells
ovum
Zona pellucida
Crona radiata
Liquor folliculi
Granulosa cells
Theca cells
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5. 2- ovulation2- ovulation
 The estradiol level reachs its peakThe estradiol level reachs its peak (200-300 pg/ml)(200-300 pg/ml) about 48about 48
hours before ovulation and lasting for 48 hours this leadhours before ovulation and lasting for 48 hours this lead
to LH surge . 24 hours following LH surge the graafianto LH surge . 24 hours following LH surge the graafian
follicle rupture . The ovum being discharged into or veryfollicle rupture . The ovum being discharged into or very
close the ostium of the fallopian tube .close the ostium of the fallopian tube .
 At ovulation the ovum has undergone the first meioticAt ovulation the ovum has undergone the first meiotic
division reducing the number of chromosomes from 46 todivision reducing the number of chromosomes from 46 to
23 and casting off the first polar body . The second23 and casting off the first polar body . The second
maturation division occurs after fertilization .maturation division occurs after fertilization .
 At this time the ovum is surrounded by a pale stainingAt this time the ovum is surrounded by a pale staining
zone the zona pellucida and out side this is a ring ofzone the zona pellucida and out side this is a ring of
granulosa cells the corona radiatagranulosa cells the corona radiata
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6. Corpus haemorrhagcum :Corpus haemorrhagcum :
The rupture of the follicle and release of the ovum isThe rupture of the follicle and release of the ovum is
attended by capillary bleeding . The blood replaces theattended by capillary bleeding . The blood replaces the
follicular fluid and the remaining part of the graafianfollicular fluid and the remaining part of the graafian
follicle becomes the corpus haemorrhagcum .follicle becomes the corpus haemorrhagcum .
Corpus luteum :Corpus luteum :
Through the continued action of LH the granulosa cellsThrough the continued action of LH the granulosa cells
soon become luteinized and a corpus luteum result . Thesoon become luteinized and a corpus luteum result . The
granulosa cells and the theca interna cells increases ingranulosa cells and the theca interna cells increases in
size and take a swollen appearance .during this processsize and take a swollen appearance .during this process
fluid rich in carotene is deposited within the cellfluid rich in carotene is deposited within the cell
cytoplasm giving the corpus luteum an increasingly acytoplasm giving the corpus luteum an increasingly a
yellow colour .as development proceed the cells of theyellow colour .as development proceed the cells of the
corpus luteum become thrown into folds as they collapsecorpus luteum become thrown into folds as they collapse
into the empty cavity giving a characteristic appearance .into the empty cavity giving a characteristic appearance .
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7.  The corpus luteum continues to grow and function aidedThe corpus luteum continues to grow and function aided
by the pulsatile secretion of LH until about day 23 or 24by the pulsatile secretion of LH until about day 23 or 24
of the cycle when it begins to regress . If the ovumof the cycle when it begins to regress . If the ovum
which was discharged at the time of ovulation is fertilizedwhich was discharged at the time of ovulation is fertilized
this regression does not take place . The corpus luteumthis regression does not take place . The corpus luteum
continues to function as the corpus luteum of pregnancycontinues to function as the corpus luteum of pregnancy
being maintained by LH effect of HCG . in the absencebeing maintained by LH effect of HCG . in the absence
of pregnancy the corpus luteum becomes progressivelyof pregnancy the corpus luteum becomes progressively
less sensitive to LH stimulation .less sensitive to LH stimulation .
 As the corpus luteum regresses it becomes hyalinizedAs the corpus luteum regresses it becomes hyalinized
and has a characteristic convoluted structure that can beand has a characteristic convoluted structure that can be
seen histologicaly and called the corpus albicans . Thisseen histologicaly and called the corpus albicans . This
concides with fall in estrogen and progesterone until theconcides with fall in estrogen and progesterone until the
endometrium can not be maintained and menstruationendometrium can not be maintained and menstruation
occurs.occurs.
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8. The endometrial cycleThe endometrial cycle
1- proliferative phase :1- proliferative phase :
- Immediately following menstruation the endometrium isImmediately following menstruation the endometrium is
thin.glands are narrow and straight and are lined bythin.glands are narrow and straight and are lined by
cuboidal epithelium , the stroma is compact .cuboidal epithelium , the stroma is compact .
- The action of estrogen coming from the graafian follicleThe action of estrogen coming from the graafian follicle
on this thin uterine lining is to produce growth of allon this thin uterine lining is to produce growth of all
elements Present. The glands become longer but remainelements Present. The glands become longer but remain
straight . The epithelium lining becomes tall andstraight . The epithelium lining becomes tall and
columnar the nucli occuping a basal position . Thecolumnar the nucli occuping a basal position . The
stroma cells increase in number and become morestroma cells increase in number and become more
loosely packed together .loosely packed together .
- The whole stroma being vascular and abundant .The whole stroma being vascular and abundant .
- The endometrium is about 3-4 mm .The endometrium is about 3-4 mm .
The endometrial changes are divided into three phases
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9. 2- secretary phase :2- secretary phase :
- Following ovulation and the addition of progesterone activity toFollowing ovulation and the addition of progesterone activity to
estrogen effect (coming from the corpus luteum) the glandsestrogen effect (coming from the corpus luteum) the glands
become more tortuous and cork screw like .become more tortuous and cork screw like .
- The epithelium lining demonstrates a series of changes duringThe epithelium lining demonstrates a series of changes during
which the nuclei become displaced from their basal position towardswhich the nuclei become displaced from their basal position towards
the centre of the cell by the formation of subnuclear vacules .the centre of the cell by the formation of subnuclear vacules .
- The glands lumina are seen to contain more secretion .as the daysThe glands lumina are seen to contain more secretion .as the days
go by until maximum secretion is achieved about day 25-of a 28go by until maximum secretion is achieved about day 25-of a 28
days cycle .the secretion is rich in glycogen.days cycle .the secretion is rich in glycogen.
- Stromal cells become further increase in size and are looselyStromal cells become further increase in size and are loosely
arranged .arranged .
- The endometrium become differentiated into three layers.The endometrium become differentiated into three layers.
- 1 the superficial compact layer around the neck of the glands.1 the superficial compact layer around the neck of the glands.
- 2 middle spongy layer around the distended lumen of the gland.2 middle spongy layer around the distended lumen of the gland.
- 3 deep compact layer around the basal part of the glands.3 deep compact layer around the basal part of the glands.
- The arterioles of the endometrium become more coiled .The arterioles of the endometrium become more coiled .
- The endometrium thickness is about 6-8 mm.The endometrium thickness is about 6-8 mm.
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10. 3- menstrual bleeding phase :3- menstrual bleeding phase :
 With regression of the corpus luteum the levels ofWith regression of the corpus luteum the levels of
estrogen and progesterone in the blood fall and theestrogen and progesterone in the blood fall and the
maintainence of the endometrium is withdrawn ,shrinkagemaintainence of the endometrium is withdrawn ,shrinkage
occurs and there is constriction of the spiral arterioles,occurs and there is constriction of the spiral arterioles,
stasis ,necrosis and bleeding .stasis ,necrosis and bleeding .
 The endometrium with the exception of the deeper basalThe endometrium with the exception of the deeper basal
zone which remain an effective blood supply breaks downzone which remain an effective blood supply breaks down
and is cast off as menstrual flow.and is cast off as menstrual flow.
 Concentration of prostaglandin F2Concentration of prostaglandin F2 alfaalfa increases throughincreases through
out the menstrual cycleout the menstrual cycle .. the highest amounts arethe highest amounts are
measured at the time of menstrual flow this potentmeasured at the time of menstrual flow this potent
vasoconstrictor probably plays a key rote in initiating spiralvasoconstrictor probably plays a key rote in initiating spiral
arteriolar spasm .arteriolar spasm .
 The endometrial surface diminishes to 1.25 mm during thisThe endometrial surface diminishes to 1.25 mm during this
phase in a course of several hours .phase in a course of several hours .www.doctor.sdwww.doctor.sd

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12. Clinical aspects of normal menstruationClinical aspects of normal menstruation
 Age of onset of menstruation (menarche) :Age of onset of menstruation (menarche) :
- the first period usually occur at about 12 yrs ,- the first period usually occur at about 12 yrs ,
but menses may appear at the age of 10 or maybut menses may appear at the age of 10 or may
be delayed until 16 without being consideredbe delayed until 16 without being considered
abnormalabnormal
- Many factors are responsible for this wideMany factors are responsible for this wide
variation . The most significant are race, heredityvariation . The most significant are race, heredity
, the general health , nutrition status and the, the general health , nutrition status and the
body mass of the individual girl .body mass of the individual girl .
- Before 10 yrs its called precocious menstruationBefore 10 yrs its called precocious menstruation
- After 16 yrs its called delayed menstruation .After 16 yrs its called delayed menstruation .
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13. Cycle length :Cycle length :
- The normal interval from the begining of- The normal interval from the begining of
one period to the onset of the next periodone period to the onset of the next period
is 28 + 7 days (21 -35)is 28 + 7 days (21 -35)
- The postovulatory phase is constant at 14The postovulatory phase is constant at 14
+ 2 days where as the preovulatory+ 2 days where as the preovulatory
interval be as short as 3 or 4 days or asinterval be as short as 3 or 4 days or as
long as 21 days .long as 21 days .
- Patient with short cycle less than 21 daysPatient with short cycle less than 21 days
are said to have polymenorrhoea .are said to have polymenorrhoea .
- If the cycle interval are long (45 – 60) theIf the cycle interval are long (45 – 60) the
condition is called oligomenorrhoeacondition is called oligomenorrhoea
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14. Duration of flow :-Duration of flow :-
- The usual length of flow is 5 + 2 days (3-7)The usual length of flow is 5 + 2 days (3-7)
- Extremely short or scanty periods are calledExtremely short or scanty periods are called
hypomenorrhoea .hypomenorrhoea .
- Where as unusually long or profuse menses are referredWhere as unusually long or profuse menses are referred
to as hypermenorrhoea (menorrhagia)to as hypermenorrhoea (menorrhagia)
Amount of flow :-Amount of flow :-
- the amount of loss at each period varies greatly . Thethe amount of loss at each period varies greatly . The
average is about 40 ml + 2o mlaverage is about 40 ml + 2o ml
- A loss more than 80 ml is considered abnormalA loss more than 80 ml is considered abnormal
(menorrhagia)(menorrhagia)
Character of flow :-Character of flow :-
- The menstrual discharge consist of blood rich inThe menstrual discharge consist of blood rich in
leucocytes , mucus and desquamated particles ofleucocytes , mucus and desquamated particles of
endometrium .endometrium .
- It is usually dark red and has characteristic musty odorIt is usually dark red and has characteristic musty odor
and do not clot under normal circumstances .and do not clot under normal circumstances .
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15. fertilizationfertilization
 FertilizationFertilization
 Is the process of fusion of the spermatozoon with theIs the process of fusion of the spermatozoon with the
mature ovum.mature ovum.
 It begins with sperm egg collision and end withIt begins with sperm egg collision and end with
production of a mononuclear single cell called the zygoteproduction of a mononuclear single cell called the zygote
and result in restoration of the chromosomes number toand result in restoration of the chromosomes number to
46 pairs.46 pairs.
 Almost always fertilization occurs in the ampullary part ofAlmost always fertilization occurs in the ampullary part of
the uterine tubes.the uterine tubes.
 Immediately following ovulation the ovum is picked up byImmediately following ovulation the ovum is picked up by
the tubal fimbriae which partly envelope the ovary. Thethe tubal fimbriae which partly envelope the ovary. The
pick up action might be muscular, or a kind of suction orpick up action might be muscular, or a kind of suction or
by ciliary action or chemotaxis exerted by the tubeby ciliary action or chemotaxis exerted by the tube
secretion.secretion.
 The ovum is rapidly trasported to the ampullary part ofThe ovum is rapidly trasported to the ampullary part of
the tube .the tube .
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16.  Out of hundreds of millions of sperms deposited in theOut of hundreds of millions of sperms deposited in the
vagina only thousands enter the uterine tube while onlyvagina only thousands enter the uterine tube while only
about 300 to 500 reach the ovum .it takes one hour forabout 300 to 500 reach the ovum .it takes one hour for
the sperm to reach its site.the sperm to reach its site.
 Complete dissolution of the cells of the corona radiataComplete dissolution of the cells of the corona radiata
occurs probably by the chemical action of theoccurs probably by the chemical action of the
hyaluronidase enzyme liberated from the acrosomal caphyaluronidase enzyme liberated from the acrosomal cap
of the hundreds of sperms present at the site or by theof the hundreds of sperms present at the site or by the
action of mucosal enzymes .action of mucosal enzymes .
 More than one sperm may penetrate the zona pellucida .More than one sperm may penetrate the zona pellucida .
This penetration is probably facilitated by the release ofThis penetration is probably facilitated by the release of
hyaluronidase enzymes from sperm acrosomal cap .hyaluronidase enzymes from sperm acrosomal cap .
Only one sperm touches the vitalline membrane . SoonOnly one sperm touches the vitalline membrane . Soon
penetration of the other sperms is prevented by zonalpenetration of the other sperms is prevented by zonal
reaction and vitelline block .reaction and vitelline block .
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17. -- Completion of the second meiotic division of the oocyteCompletion of the second meiotic division of the oocyte
immediatly follows with formation of two cells each hasimmediatly follows with formation of two cells each has
haploid number of chromosomes (23x) the bigger one ishaploid number of chromosomes (23x) the bigger one is
called the female pronucleus and the small one is calledcalled the female pronucleus and the small one is called
second polar body which is pushed to the perivitellinesecond polar body which is pushed to the perivitelline
spacespace
- The head and neck of the spermatozoon become maleThe head and neck of the spermatozoon become male
pronucleus containig hapliod number of chromosomespronucleus containig hapliod number of chromosomes
(23x) or (23y)(23x) or (23y)
- The male and female pronuclei unite to form the zygoteThe male and female pronuclei unite to form the zygote
with restoration of the diploid number of chromosomeswith restoration of the diploid number of chromosomes
(46xx) or (46xy)(46xx) or (46xy)
- Sex of the child is determined by the pattern of the sexSex of the child is determined by the pattern of the sex
chromosomes supplied by the spermatozoon . If thechromosomes supplied by the spermatozoon . If the
spermatozoon contain x chromosome a female embryospermatozoon contain x chromosome a female embryo
(46xx) is formed if it contain a y chromosome a male(46xx) is formed if it contain a y chromosome a male
embryo (46xy) is formed .embryo (46xy) is formed .
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18. - after the zygote formation typical mitotic division of theafter the zygote formation typical mitotic division of the
nucleus occurs producing two blastomeres . This twonucleus occurs producing two blastomeres . This two
cells stage is reached approximately 30 hours aftercells stage is reached approximately 30 hours after
fertilization each contain equal cytoplasmic volume andfertilization each contain equal cytoplasmic volume and
chromosome numbers .chromosome numbers .
- the blastomeres continue to divide by binarry divisionthe blastomeres continue to divide by binarry division
through 4,8,16 cells stage until a cluster of cells isthrough 4,8,16 cells stage until a cluster of cells is
formed and is called morulaformed and is called morula
- The morula after spending about 3 day in the uterineThe morula after spending about 3 day in the uterine
tube enters the uterine cavity .tube enters the uterine cavity .
- The central cells of the morula is known as inner cellsThe central cells of the morula is known as inner cells
mass which forms the embryo proper and the peripheralmass which forms the embryo proper and the peripheral
cells are called the outer cells mass which will formcells are called the outer cells mass which will form
protective and nutritive membrane of the embryo .protective and nutritive membrane of the embryo .
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19. - While the morula remains free in the uterine cavity onWhile the morula remains free in the uterine cavity on
the 4the 4thth
and 5and 5thth
day it is covered by a film of mucus . Theday it is covered by a film of mucus . The
fluid passes through the canaliculi of the zona pellucidafluid passes through the canaliculi of the zona pellucida
which separates the cells of the morula and is nowwhich separates the cells of the morula and is now
termed blastocysttermed blastocyst
- Implantation occurs at this blastocyst stage , 6 to 8 daysImplantation occurs at this blastocyst stage , 6 to 8 days
after ovulation .after ovulation .
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