Menstrual Cycle
Content
Menstruation – is the periodic discharge of blood, mucus and
epithelial cells from the uterus.
Menstrual Cycle – periodic uterine bleeding in response to cyclic
hormonal changes. A process that allows for conception and
implantation of new life.
It is usually determined by counting as day 1 the 1st day of a
menstrual period until the last day before the next menstrual period.
Purpose:
To bring an ovum to maturity
To renew a uterine tissue bed that will be responsive to fetal
growth
To prepare the uterus for pregnancy
Characteristics of Normal Menstrual Cycles
TERM
DESCRIPTION
Beginning (Menarche)
average age of onset: 12 or 13 years;
average range of age: 9-17 years
Interval between cycles
average 28 days; cycles of 23 to 35
days not usual
Duration of Menstrual flow
average flow: 2-7 days; ranges 1-9
days not normal
Amount of menstrual flow
difficult to estimate; average 30 to 80
ml. per menstrual period; saturating a
pad in less than an hour is considered
heavy bleeding.
Color of menstrual flow
dark red; a combination of blood,
mucus, and endometrial cells
Odor of menstrual flow
marigold
Discomforts of Menstruation
1.
Breast tenderness and feeling of fullness
2.
Tendency towards fatigue
3.
Temperament and mood changes – because of hormonal
influence and decreased levels of estrogen and progesterone
4.
Discomfort in pelvic area, lower back and legs
5.
Retained fluids and weight gain
Abnormalities of Menstruation
1.
Amenorrhea – absence of menstrual flow
2.
Dysmenorrhea – painful menstruation
3.
Oligomenorrhea – scanty menstruation
4.
Polymenorrhea – too frequent menstruation
5.
Menorrhagia -excessive menstrual bleeding
6.
Metrorrhagia – bleeding between periods of less than 2 weeks
7.
Hypomenorrhea – abnormally short menstruation
8.
Hypermenorrhea – abnormally long menstruation
Four body structure involved in the physiology of the
menstrual cycle:
1.
Hypothalamus
2.
Pituitary gland
3.
Ovaries
4.
Uterus
Reproductive Hormones:
1.
Gonodotropin-Releasing
Hormone (GnRH)
Stimulates release of FSH
and LH initiating puberty and
sustaining menstrual cycle.
22
Follicle-stimulating Hormone
(FSH)
secreted by anterior
pituitary gland during the 1st half of menstrual cycle
stimulate growth and maturation of graafian follicle
before ovulation
22
thins the endometrium
Luteinizing Hormone (LH)
secreted by the anterior pituitary gland
stimulates final maturation of graafian follicle
surge of LH about 14 days before next menstrual period
causes ovulation
stimulates transformation of graafian follicle into corpus
luteum
22
thickens the endometrium
Estrogen
secreted primarily by the ovaries, corpus luteum, adrenal
cortex and placenta in pregnancy
considered the Hormone of Women
stimulates thickening of the endometrium; causes
suppression of FSH secretion
responsible for the development of secondary sex
characteristics
stimulates uterine contractions
increases water content of uterus
high estrogen concentration inhibits secretion of FSH and
Prolactin but stimulates secretion of LH7.
low estrogen concentration after pregnancy stimulates
secretion of Prolactin
22
Progesterone
secreted by the ovary, corpus luteum and placenta
during pregnancy
inhibits secretion of LH
has thermogenic effect (increases body temperature)
relaxes smooth muscles thereby decreases contractions
of uterus
causes cervical secretion of thick mucus
maintain thickness of endometrium
allows pregnancy to be maintained = Hormone of
Pregnancy
22
22
prepares breasts for lactation
Prolactin
secreted by the anterior pituitary gland
stimulates secretion of milk
Oxytocin
secreted by the posterior pituitary gland
stimulates uterine contractions during birth and compress
uterine blood vessels and control bleeding
stimulates let-down or milk-ejection reflex during
breastfeeding
22
Prostaglandins
fatty acids’ categorized as hormones
produced by many organs of the body, including the
endometrium
affects menstrual cycle
influences the onset and maintenance of labor
Puberty
Menstruation
Hygiene
Myths
Phases of Menstrual cycle
The day count for menstrual cycle begins on the first day of menstruation when blood starts to come
out of the vagina. In this section, the length of menstrual cycle has been assumed to be 28 days
(which is the average among women). The entire duration of a Menstrual cycle can be divided into
four main phases:
1.
2.
Menstrual phase (From day 1 to 5)
Follicular phase (From day 1 to 13)
3.
Ovulation phase (Day 14)
4.
Luteal phase (From day 15 to 28)
Menstrual phase (day 1-5)
Menstrual phase begins on the first day of menstruation and lasts till the 5th day of the menstrual
cycle. The following events occur during this phase:
The uterus sheds its inner lining of soft tissue and blood vessels which exits the body from
the vagina in the form of menstrual fluid.
Blood loss of 10 ml to 80 ml is considered normal.
You may experience abdominal cramps. These cramps are caused by the contraction of the
uterine and the abdominal muscles to expel the menstrual fluid.
Follicular phase (day 1-13)
This phase also begins on the first day of menstruation, but it lasts till the 13th day of the menstrual
cycle. The following events occur during this phase:
The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow.
One of these egg cells begins to mature in a sac-like-structure called follicle. It takes 13 days
for the egg cell to reach maturity.
While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to
develop a lining of blood vessels and soft tissue called endometrium.
Ovulation phase (day 14)
On the 14th day of the cycle, the pituitary gland secretes a hormone that causes the ovary to release
the matured egg cell. The released egg cell is swept into the fallopian tube by the cilia of the
fimbriae. Fimbriae are finger like projections located at the end of the fallopian tube close to the
ovaries and cilia are slender hair like projections on each Fimbria.
Luteal phase (day 15-28)
This phase begins on the 15th day and lasts till the end of the cycle. The following events occur
during this phase:
The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours.
If a sperm cell does not impregnate the egg cell within that time, the egg cell disintegrates.
The hormone that causes the uterus to retain its endometrium gets used up by the end of the
menstrual cycle. This causes the menstrual phase of the next cycle to begin.
epithelial cells from the uterus.
Menstrual Cycle – periodic uterine bleeding in response to cyclic
hormonal changes. A process that allows for conception and
implantation of new life.
It is usually determined by counting as day 1 the 1st day of a
menstrual period until the last day before the next menstrual period.
Purpose:
To bring an ovum to maturity
To renew a uterine tissue bed that will be responsive to fetal
growth
To prepare the uterus for pregnancy
Characteristics of Normal Menstrual Cycles
TERM
DESCRIPTION
Beginning (Menarche)
average age of onset: 12 or 13 years;
average range of age: 9-17 years
Interval between cycles
average 28 days; cycles of 23 to 35
days not usual
Duration of Menstrual flow
average flow: 2-7 days; ranges 1-9
days not normal
Amount of menstrual flow
difficult to estimate; average 30 to 80
ml. per menstrual period; saturating a
pad in less than an hour is considered
heavy bleeding.
Color of menstrual flow
dark red; a combination of blood,
mucus, and endometrial cells
Odor of menstrual flow
marigold
Discomforts of Menstruation
1.
Breast tenderness and feeling of fullness
2.
Tendency towards fatigue
3.
Temperament and mood changes – because of hormonal
influence and decreased levels of estrogen and progesterone
4.
Discomfort in pelvic area, lower back and legs
5.
Retained fluids and weight gain
Abnormalities of Menstruation
1.
Amenorrhea – absence of menstrual flow
2.
Dysmenorrhea – painful menstruation
3.
Oligomenorrhea – scanty menstruation
4.
Polymenorrhea – too frequent menstruation
5.
Menorrhagia -excessive menstrual bleeding
6.
Metrorrhagia – bleeding between periods of less than 2 weeks
7.
Hypomenorrhea – abnormally short menstruation
8.
Hypermenorrhea – abnormally long menstruation
Four body structure involved in the physiology of the
menstrual cycle:
1.
Hypothalamus
2.
Pituitary gland
3.
Ovaries
4.
Uterus
Reproductive Hormones:
1.
Gonodotropin-Releasing
Hormone (GnRH)
Stimulates release of FSH
and LH initiating puberty and
sustaining menstrual cycle.
22
Follicle-stimulating Hormone
(FSH)
secreted by anterior
pituitary gland during the 1st half of menstrual cycle
stimulate growth and maturation of graafian follicle
before ovulation
22
thins the endometrium
Luteinizing Hormone (LH)
secreted by the anterior pituitary gland
stimulates final maturation of graafian follicle
surge of LH about 14 days before next menstrual period
causes ovulation
stimulates transformation of graafian follicle into corpus
luteum
22
thickens the endometrium
Estrogen
secreted primarily by the ovaries, corpus luteum, adrenal
cortex and placenta in pregnancy
considered the Hormone of Women
stimulates thickening of the endometrium; causes
suppression of FSH secretion
responsible for the development of secondary sex
characteristics
stimulates uterine contractions
increases water content of uterus
high estrogen concentration inhibits secretion of FSH and
Prolactin but stimulates secretion of LH7.
low estrogen concentration after pregnancy stimulates
secretion of Prolactin
22
Progesterone
secreted by the ovary, corpus luteum and placenta
during pregnancy
inhibits secretion of LH
has thermogenic effect (increases body temperature)
relaxes smooth muscles thereby decreases contractions
of uterus
causes cervical secretion of thick mucus
maintain thickness of endometrium
allows pregnancy to be maintained = Hormone of
Pregnancy
22
22
prepares breasts for lactation
Prolactin
secreted by the anterior pituitary gland
stimulates secretion of milk
Oxytocin
secreted by the posterior pituitary gland
stimulates uterine contractions during birth and compress
uterine blood vessels and control bleeding
stimulates let-down or milk-ejection reflex during
breastfeeding
22
Prostaglandins
fatty acids’ categorized as hormones
produced by many organs of the body, including the
endometrium
affects menstrual cycle
influences the onset and maintenance of labor
Puberty
Menstruation
Hygiene
Myths
Phases of Menstrual cycle
The day count for menstrual cycle begins on the first day of menstruation when blood starts to come
out of the vagina. In this section, the length of menstrual cycle has been assumed to be 28 days
(which is the average among women). The entire duration of a Menstrual cycle can be divided into
four main phases:
1.
2.
Menstrual phase (From day 1 to 5)
Follicular phase (From day 1 to 13)
3.
Ovulation phase (Day 14)
4.
Luteal phase (From day 15 to 28)
Menstrual phase (day 1-5)
Menstrual phase begins on the first day of menstruation and lasts till the 5th day of the menstrual
cycle. The following events occur during this phase:
The uterus sheds its inner lining of soft tissue and blood vessels which exits the body from
the vagina in the form of menstrual fluid.
Blood loss of 10 ml to 80 ml is considered normal.
You may experience abdominal cramps. These cramps are caused by the contraction of the
uterine and the abdominal muscles to expel the menstrual fluid.
Follicular phase (day 1-13)
This phase also begins on the first day of menstruation, but it lasts till the 13th day of the menstrual
cycle. The following events occur during this phase:
The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow.
One of these egg cells begins to mature in a sac-like-structure called follicle. It takes 13 days
for the egg cell to reach maturity.
While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to
develop a lining of blood vessels and soft tissue called endometrium.
Ovulation phase (day 14)
On the 14th day of the cycle, the pituitary gland secretes a hormone that causes the ovary to release
the matured egg cell. The released egg cell is swept into the fallopian tube by the cilia of the
fimbriae. Fimbriae are finger like projections located at the end of the fallopian tube close to the
ovaries and cilia are slender hair like projections on each Fimbria.
Luteal phase (day 15-28)
This phase begins on the 15th day and lasts till the end of the cycle. The following events occur
during this phase:
The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours.
If a sperm cell does not impregnate the egg cell within that time, the egg cell disintegrates.
The hormone that causes the uterus to retain its endometrium gets used up by the end of the
menstrual cycle. This causes the menstrual phase of the next cycle to begin.
