PUBERTY
This increase influences the following:
-Is the stage of life at which secondary sex changes
- development of the uterus, fallopian tubes, and
begin.
vagina;
-In most girls, these changes are stimulated when
- typical female fat distribution;
the hypothalamus synthesizes and releases
- hair patterns; and
gonadotropin-releasing hormone (GnRH), which then
- breast development.
triggers the anterior pituitary to release follicle-
-It also closes the epiphyses of long bones in girls
stimulating hormone (FSH) and luteinizing hormone
the same way testosterone closes the growth plate in
(LH).
boys.
-FSH and LH are termed gonadotropin (gonad=
-The beginning of breast development is termed
“ovary”; tropin = “growth”) hormones not only because
thelarche, which usually starts 1 to 2 years before
menstruation.
they begin the production of androgen and estrogen,
which in turn initiate secondary sex characteristics,
but also because they continue to cause the
MENSTRUATION
production of eggs and influence menstrual cycles
-A menstrual cycle (the female reproductive cycle) is
throughout women’s lives
episodic uterine bleeding in response to cyclic
THE ROLE OF ANDROGEN
Androgenic hormones are the hormones responsible
for:
1) muscular development
2) physical growth
3) increase in sebaceous gland secretions that cause
typical acne in both boys and girls during adolescence.
In males, androgenic hormones are produced by the
adrenal cortex and the testes and, in females, by the
adrenal cortex and the ovaries.
hormonal changes.
-The purpose of a menstrual cycle is to bring an ovum
to maturity and renew a uterine tissue bed that will
be necessary for the ova’s growth should it be
fertilized.
Menarche
-First menstruation
-May occur as early as 9 years of age
-It is good to include health teaching information on
menstruation to both school-age children and their
THE ROLE OF ANDROGEN IN MALES
parents as early as fourth grade as part of routine
care.
The level of the primary androgenic hormone,
The length of menstrual cycles
testosterone, is low in males until puberty (between
ages 12 and 14 years) when it rises to influence
pubertal changes in the testes, scrotum, penis,
prostate, and seminal vesicles; the appearance of
male pubic, axillary, and facial hair; laryngeal
enlargement with its accompanying voice change;
-differs from woman to woman.
-average length is 28 days (from the beginning of one
menstrual flow to the beginning of the next).
-It is not unusual for cycles to be as short as 23 days
or as long as 35 days.
maturation of spermatozoa; and closure of growth
The length of the average menstrual flow (termed
plates in long bones (termed adrenarche).
menses)
THE ROLE OF ANDROGEN IN GIRLS
-4 to 6 days
-although women may have flows as short as 2 days or
In girls, testosterone influences the following:
as long as 9 days
1)enlargement of the labia majora and clitoris
2) formation of axillary and pubic hair.
Characteristics
Beginning (menarche)
THE ROLE OF ESTROGEN
When triggered at puberty by FSH, ovarian follicles
in females begin to excrete a high level of the
hormone estrogen.
Interval between cycles
Description
Average age at onset,
12.4 years; average
range, 9–17 years
Average, 28 days;
cycles of 23–35 days
not unusual
Duration of menstrual
flow
Amount
Color
Odor
Average flow, 4–6 days;
ranges of 2–9 days not
abnormal
-Difficult to estimate;
-Average 30–80 ml per
menstrual period;
-Saturating a pad or
tampon in less than 1 hr
is heavy bleeding
Dark red;
•A combination of blood,
mucus, and endometrial
cells
Similar to marigolds
The Ovaries
-Every month during the fertile period of a woman’s
life (from menarche to menopause), one of the
ovary’s oocytes is activated by FSH to begin to grow
and mature.
-As the oocyte grows, its cells produce a clear fluid
(follicular fluid) that contains a high degree of
estrogen and some progesterone.
-As the follicle surrounding the oocyte grows, it is
propelled toward the surface of the ovary.
-At full maturity, the follicle is visible on the surface
of the ovary as a clear water blister approximately
0.25 to 0.5 in. across.
-At this stage of maturation, the small ovum (barely
visible to the naked eye, about the size of a printed
THE PHYSIOLOGY OF MENSTRUATION
period) with its surrounding follicular membrane and
fluid is termed a Graafian follicle.
Four body structures are involved:
By day 14 or the midpoint of a typical 28-day cycle,
1. Hypothalamus
2. Anterior pituitary gland
the ovum has divided by mitotic division into two
separate bodies:
3. Ovaries
1.)a primary oocyte, which contains the bulk of the
4. Uterus
cytoplasm, and
- For a menstrual cycle to be complete, all four
2) a secondary oocyte, which contains so little
organs must contribute their part;
cytoplasm that it is not functional.
-Inactivity of any part results in an incomplete or
ineffective cycle
-The structure also has accomplished its meiotic
The Hypothalamus
division, reducing its number of chromosomes to the
haploid (having only one member of a pair) number of
23.
-Release of the GnRH (also called luteinizing
-After an upsurge of LH from the pituitary at about
hormone–releasing hormone [LHRH]) from the
day 14, prostaglandins are released and the graafian
hypothalamus initiates the menstrual cycle.
follicle ruptures.
-GnRH then stimulates the pituitary gland to send
-The ovum is set free from the surface of the ovary,
the gonadotropic hormone to the ovaries to produce
a process termed ovulation. It is swept into the open
estrogen.
end of a fallopian tube.
-When the level of estrogen rises, release of GnRH is
-It is important to teach women that ovulation does
repressed and no further menstrual cycles will occur.
not necessarily occur on the 14th day of their cycle;
The Anterior lobe of the Pituitary Gland (the
adenohypophysis)
-Under the influence of GnRH, produces two
hormones:
1)FSH, a hormone active early in the cycle that is
responsible for maturation of the ovum
2)LH, a hormone that becomes most active at the
midpoint of the cycle and is responsible for ovulation,
or release of the mature egg cell from the ovary.
-> It also stimulates growth of the uterine lining
during the second half of the menstrual cycle.
-it occurs 14 days before the end of their cycle.
-If their menstrual cycle is only 20 days long, for
example, their day of ovulation would be day 6 (14
days before the end of the cycle).
If their cycle is 44 days long, ovulation would occur
on day 30, not at the halfway point—day 22.
After the ovum and the follicular fluid have been
discharged from the ovary, the cells of the follicle
remain in the form of a hollow, empty pit.
-The FSH has done its work at this point and now
decreases in amount.
-The second pituitary hormone, LH, continues to rise
in amount and directs the follicle cells left behind in
the ovary to produce lutein, a bright-yellow fluid high
in progesterone.
quantities of glycogen (an elementary sugar) and
-With lutein production, the follicle is renamed a
mucin (a protein).
corpus luteum (yellow body).
-It takes on the appearance of rich, spongy velvet.
-The basal body temperature of a woman drops
-Is termed the progestational, luteal, premenstrual,
slightly (by 0.5° to 1°F) just before the day of
or secretory phase.
ovulation because of the extremely low level of
progesterone that is present at that time.
The Third Phase of the Menstrual Cycle (Ischemic)
-It rises by 1°F on the day after ovulation because of
-If fertilization does not occur, the corpus luteum in
the concentration of progesterone, which is
the ovary begins to regress after 8 to 10 days, and
thermogenic.
therefore, the production of progesterone
-The woman’s temperature remains at this elevated
decreases.
level until approximately day 24 of the menstrual
-With the withdrawal of progesterone, the
cycle, when the progesterone level again decreases
endometrium of the uterus begins to degenerate (at
-If conception (fertilization by a spermatozoon)
about day 24 or day 25 of the cycle).
occurs as the ovum proceeds down a fallopian tube
-The capillaries rupture, with minute hemorrhages,
and the endometrium sloughs off.
and the fertilized ovum implants on the endometrium
of the uterus, the corpus luteum remains throughout
the major portion of the pregnancy (to about 16 to
20 weeks).
-If conception does not occur, the unfertilized ovum
atrophies after 4 or 5 days, and the corpus luteum
(now called a “false” corpus luteum) remains for only
8 to 10 days. --As the corpus luteum regresses, it is
gradually replaced by white fibrous tissue, and the
resulting structure is termed a corpus albicans (white
body).
The Uterus
Uterine changes that occur monthly as a result of
stimulation from the estrogen and progesterone
produced by the ovaries.
The First Phase of the Menstrual Cycle
(Proliferative)
-Immediately after a menstrual flow (which occurs
during the first 4 or 5 days of a cycle)
-the endometrium, or lining of the uterus, is very
thin, approximately one cell layer in depth.
-As the ovary begins to produce estrogen (in the
follicular fluid, under the direction of the pituitary
FSH), the endometrium begins to proliferate so
rapidly the thickness of the endometrium increases
as much as eightfold from day 5 to day 14.
-ALSO CALLED the proliferative, estrogenic,
follicular, or postmenstrual phase.
The Fourth Phase of the Menstrual Cycle (Menses)
*Menses, or a menstrual flow, is composed of
a) a mixture of blood from the ruptured capillaries;
b)mucin;
c) fragments of endometrial tissue;
d) and the microscopic, atrophied, and unfertilized
ovum.
-Because it is the only external marker of the cycle,
however, the first day of menstrual flow is used to
mark the beginning day of a new menstrual cycle.
-Contrary to common belief, a menstrual flow
contains only 30 to 80 ml of blood;
-if it seems to be more, it is because of the
accompanying mucus and endometrial shreds.
-The iron loss in a typical menstrual flow is
approximately 11 mg.
-This is enough loss that many adolescent women
could benefit from a daily iron supplement to prevent
iron depletion during their menstruating years
CERVICAL CHANGES
-The mucus of the uterine cervix also changes in
structure and consistency each month during a
menstrual cycle.
-At the beginning of each cycle, when estrogen
secretion from the ovary is low
a) Cervical mucus is thick and scant.
b) Sperm survival in this type of mucus is poor.
The Second Phase of the Menstrual Cycle
-At the time of ovulation, when the estrogen level
(Secretory)
has risen to a high point: a) Cervical mucus becomes
thin, stretchy (spinnbarkeit), and copious.
*After ovulation, the formation of progesterone in
the corpus luteum (under the direction of LH) causes
the glands of the uterine endometrium to become
corkscrew or twisted in appearance and dilated with
Spinnbarkeit
Sperm penetration and survival in this thin mucus are
both excellent.
The second half of the cycle
a) progesterone becomes the major influencing
hormone
b) cervical mucus again thickens
c) sperm survival is again poor.
During ovulation
a) the body of the cervix is softer
b) the cervical os is slightly open
ACTIONS OF SEX HORMONES:
Estrogen and Progesterone
Estrogen
-Controls development of female secondary sex
characteristics
-Assists in the maturation of the ovarian follicles
-Causes uterus to increase in size and weight
-Increases myometrial contractility in uterus and
fallopian tubes
-Increases uterine sensitivity to oxytocin
-Inhibits FSH production Stimulates LH production
Progesterone
-Decreases uterine motility and contractility
-Causes uterine endometrium to increase its supply of
glycogen, arterial blood, secretory glands, amino
acids, and water
-Vaginal epithelium proliferates
-Causes cervix to secrete thick, viscous mucus
-Increases breast glandular tissue
-Prepares breast for lactation Hormone for
“Pregnancy”
PROSTAGLANDINS (PGs)
-Oxygenated fatty acid produced by the cells of the
endometrium
-Also classified as hormones and are found in and
around the follicle at the time of the ovulation
-Necessary for follicular rupture
OXYTOCIN
-A natural hormone secreted by the hypothalamus
and stored in the Posterior Pituitary Gland
-Manages labor and delivery and lactation Has
synthetic form for induction of labor