The Female Reproductive System
Narrow tube carrying
eggs from the ovaries
to the uterus
Has ciliated cells
Site of fertilisation
Collects eggs
released from
ovary and directs
them to the oviduct
Produces and
releases eggs
Produces hormones
oestrogen and
progesterone
Ring of muscle between vagina
and uterus
Allows sperm to pass into
uterus from vagina and blood
to pass out during
menstruation
and the baby during birth
Before ovulation, the cervix produces a special
mucus for about 3 to 9 days. This mucous is as
crucial to fertility as ovulation because without
it, the male’s sperm cannot survive nor be
transported inside the female to fertilize the
eggs. When mucous is present, it nourishes
and protects sperm allowing them to live for 3
to 5 days.
Located near
the ovaries but
not directly
connected to
them. When
an egg cell is
released, it
travels through
the oviduct by
the action of
ciliated cells
that line the
funnel like
opening of the
oviduct and
the oviduct
itself.
If sperms are
present in the
oviduct, the
egg may be
fertilized.
Produces and
releases ova into the
oviduct.
Produces hormones
Oestrogen – repairs
uterine lining after
menstruation
Progesterone –
maintains uterine
lining.
Site of implantation
of embryo;
formation of
placenta
Cavity in which
foetus develops
Muscular and elastic tube
into which male penis is
placed during intercourse
Stretches to allow baby
out at childbirth.
The Ovary
Production of Eggs
At birth, each ovary in a female has hundreds of
thousands of eggs, but they are immature and
remain dormant until her first menstrual cycle,
which occurs during puberty (sexual maturity).
Egg development – a cyclical process of 28 days.
Takes place in the ovaries. It is controlled by
hormones from the hypothalamus and the
pituitary gland.
Every 28 days or so
from puberty until
menopause
(when ovulation
and menstruation stops),
between one and three eggs, the size of
the head of a pin are released from the ovaries. This
whole process takes about three minutes and is
known as ovulation. The eggs are then move down
the fallopian tubes towards the uterus.
The Menstrual Cycle
The monthly ovarian and uterine cycle of the female
reproductive system is called the menstrual cycle. It has an
average length of about 28 days, and consists of four stages.
The menstrual cycle involves interactions of the
hypothalamus, pituitary gland,
ovary and uterus.
The cycles usually occur
regularly between puberty
and menopause. The cycle
may be interrupted by
pregnancy, illness,
or other factors (example,
extreme exercise or extreme
dieting).
1 - Follicle stage
Follicle Stimulating Hormone (FSH) is secreted by the pituitary
gland (in the brain).
FSH causes several follicles in the ovary
to begin developing. Usually, only one
matures.
As the follicle develops, it secretes oestrogen,
which stimulates the uterine lining to thicken with mucus and a
rich supply of blood vessels.
These changes prepare the uterus for a possible pregnancy.
This stage lasts 10 to 14 days.
2 - Ovulation
A high level of oestrogen in the blood causes the pituitary
gland to decrease secretion of FSH and begin secretion
of luteinizing hormone (LH).
When the concentration of LH in the blood reaches a
certain level, ovulation occurs - that is the follicle
ruptures releasing a mature egg.
Ovulation usually takes
place in about the middle
of the menstrual cycle.
3 - Corpus luteum stage
After ovulation, LH causes the ruptured follicle to fill with
cells, forming a yellow body called the corpus luteum.
The corpus luteum begins to secrete the hormone
progesterone, which maintains the continued growth of
the uterine lining.
It also prevents the
development of new follicles
in the ovary by
inhibiting the release of FSH.
This stage lasts 10 - 14 days.
4 - Menstruation
• If fertilization does not occur,
secretion of LH decreases, and the
corpus luteum degenerates.
• This results in a decrease in the level
of progesterone.
• As a result, the thickened lining of the
uterus can no longer be maintained
and it breaks down.
• The extra layers of the lining, the
unfertilized egg, and a small amount
of blood pass out of the body
through the vagina.
• This is called menstruation. It lasts
from about 3 to 7 days.