Female Reproductive organs
• Primary female
reproductive organs
are ovaries while
accessory are the
ducts like uterine
tubes, uterus, and
vagina
The Ovaries
The Ovaries
• The ovaries on the outer side
are surrounded by a layer of
epithelial cells called the
germinal epithelium.
• Embedded in their cortex are
ovarian follicles in various
stages of development.
• The remains of ruptured
follicle after ovulation is called
corpus luteum
Uterine Tubes
• Uterine tubes receive the
ovulated oocyte and provide
a site for fertilization. They
empty into the uterus.
• They expand distally around
the ovary forming the
ampulla which ends in the
funnel-shaped, ciliated
infundibulum containing
fingerlike projections called
fimbriae.
Uterine Tubes
• The uterine tubes have no
contact with the ovaries and
the ovulated oocyte is
cast into the peritoneal
cavity. Beating cilia on the
fimbriae create currents to
carry the oocyte into the
uterine tube.
• The oocyte is carried
toward the uterus by
peristalsis and ciliary action
of the lining ciliary
epithelium of the tube.
Uterus
• The uterus is a hollow,
thick-walled organ
located in the pelvis
anterior to the rectum and
posterio superior to the
urinary bladder. Its parts
are
• Fundus – rounded region
superior to the entrance of
the uterine tubes
• Body – major portion of
the uterus
• Isthmus – narrowed
region between the body
and cervix
Uterus
• Cervix – narrow neck which
projects into the vagina
inferiorly
• Cervical canal – cavity of
the cervix that
communicates with:
– The vagina via the external os
– The uterine body via the
internal os
• Cervical glands secrete
mucus that covers the
external os and blocks
sperm entry except during
midcycle
Uterine Wall
Stratum
functionalis
Stratum
basale
Endometrium
Composed of three layers
• Perimetrium – outermost serous layer; the visceral peritoneum
• Myometrium – middle layer; consists of interlacing layers of smooth
muscles
• Endometrium – mucosal lining of the uterine cavity. It has numerous
uterine glands and consists of
– Stratum functionalis: It undergoes cyclic changes in response to ovarian
hormones and is shed during menstruation
– Stratum basalis: It forms a new functionalis layer after menstruation ends. It
does not respond to ovarian hormones.
Ovarian Cycle
• Monthly series of events occurring
in ovaries associated with the
maturation of an egg is called an
ovarian cycle. It consists of follicular
phase and luteal phase
• Follicular phase – period of
follicle growth (days 1–14). During it
primordial follicle becomes primary,
secondary and tertiary follicles and
follicular cells become granulosa
cells secreting estrogen.
Ovarian Cycle
Follicular phase cont. The full
sized follicle (vesicular follicle)
bulges from the external surface of
the ovary. The primary oocyte
completes meiosis I, and the stage
is set for ovulation.
Ovulation occurs at the mid of the
cycle and a twinge of pain is
sometimes felt in pelvis at ovulation
called Mittelschmerz
Ovarian Cycle
Luteal phase – A period of
corpus luteum activity (days 14–
28). After ovulation, the ruptured
follicle collapses, granulosa cells
enlarge, and along with internal
thecal cells, form the corpus
luteum The corpus luteum
secretes progesterone and
estrogen..
Ovarian Cycle
Luteal phase cont.
If pregnancy does not occur, the
corpus luteum degenerates in 10
days, leaving a scar (corpus
albicans) in the ovary. If
pregnancy occurs, the corpus
luteum produces hormones until
the placenta takes over that role
(at about 3 months of gestation)
MENSTRUAL CYCLE
What actually
happens in
those 28 days?
The ovarian and menstrual cycle of the human female
Uterine (Endometrial) Cycle
• Monthly cyclical changes in the
endometrium of uterus for prepration
of implantation (in the event of
fertilization) and for menstruation (in
the absence of fertilization) is called
uterine cycle.
• The uterine endometrial cycle can be
divided into three phases:
– the proliferative phase,
– the secretary,
– the menstrual phase.
Uterine (Endometrial) Cycle
• Proliferative Phase
• The proliferative or follicular, phase,
spans from the end of the
menstruation until ovulation.
• Under the influence of increasing
levels of estrogen secreted by
ovarian follicles all elements of
endometrium proliferate.
• The raw surface of endometrium is
again covered with epithelium
which proliferates out from the
remains of the stems of uterine
glands. The stromal cells increase
Uterine (Endometrial) Cycle
Proliferative Phase cont.
• Endometrial glands elongate with
cells containing some glycogen.
But it is not secreted during the
follicular phase.
• Spiral arteries supplying blood
also elongate. Stratum
functionalis thus resumed
again.
Uterine (Endometrial) Cycle
Secretary Phase
• The luteal, or secretory phase,
begins at ovulation and lasts until
the menstrual phase of the next
cycle.
• At the beginning of the luteal
phase, progesterone induces the
endometrial glands to secrete
glycogen, mucus, and other
substances. These glands become
tortuous and have large lumens
due to increased secretary activity.
Uterine (Endometrial) Cycle
Secretary Phase cont.
• The spiral arteries extend into the
superficial layer of the
endometrium.
• In the absence of fertilization by
day 23 of the cycle, the corpus
luteum begins to degenerate and
consequently ovarian hormone
levels decrease.
Uterine (Endometrial Cycle)
Secretary Phase cont.
• As estrogen and progesterone
levels decrease, the
endometrium undergoes
involution.
• Days 25-26 of the menstrual
cycle, endothelin and thromboxin
begin to mediate
vasoconstriction of the spiral
arteries. The resulting ischemia
may cause some early menstrual
cramps.
Uterine (Endometrial Cycle)
Secretary Phase cont.
• By day 28 of the
menstrual cycle, intense
vasoconstriction and
subsequent ischemia
cause mass apoptosis of
the stratum functionalis.
Uterine (Endometrial) Cycle
Menstrual Phase
• The menstrual phase begins as the
spiral arteries rupture secondary to
ischemia, releasing blood into the
uterus, and the apoptosed
endometrium is sloughed off. It
usually lasts four days. During this
period, the stratum functionalis is
completely shed.
• Arterial and venous blood, remnants of
endometrial stroma and glands,
leukocytes, and red blood cells are all
present in the menstrual flow.
Hormonal control
1.
2.
3.
Pituitary gland release
Follicle Stimulating Hormone
(FSH) that acts on the ovary.
Ovarian follicles grow and
mature under influence of
FSH, and produce
increasing quantities of
estrogen
When levels of estrogen
reach a threshold level, a
feed back process
decreases the production of
FSH by the pituitary.
Hormonal control
4.
5.
6.
Increased estrogen levels
trigger the release of
Luteinizing Hormone (LH) from
the pituitary gland
Ovulation occurs, that is
release of an egg from the
follicle.
The empty follicle forms the
corpus luteum, which produces
progesterone which maintains
the endometrium in a state of
readiness to receive a fertilized
egg
Hormonal control
7. If the fertilized egg does
not implant itself the
progesterone level falls
and mensturation
commences.
Summary of Reproductive
Hormones in Females
• Hypothalamus releases Gonadotropin Releasing Hormone (GRH)
which binds with receptors in Ant. Pituitary
• Anterior Pituitary releases Follicle Stimulating Hormone (FSH) and
Luteinizing Hormone(LH) pass in blood to site of action
• FSH acts on receptors in ovaries to stimulate development of the egg
follicles
• LH causes rupture of egg follicles.
• Rupture of egg triggers production of estrogens and progestogens
from remaining tissues of follicle,corpus luteum
• These hormones travel in blood to the brain
• Hypothalamus senses levels, then may decrease release of GRH
At end of this study you are able to
• Describe structure of ovary, uterine tubes
and uterus
• Discuss the cyclic changes in the female
genital tract, which include:
– The ovarian cycle (phases and hormonal
control).
– The uterine cycle (phases and hormonal
control)