Female Reproductive
System
Our Goals This Section...
• Identify and give functions for each of the following:
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ovaries (follicles and corpus luteum)
oviducts (fallopian tubes)
uterus
endometrium
cervix
vagina
clitoris
• Describe the functions of estrogen
• Describe the sequence of events in the ovarian cycle,
with reference the follicular phase, ovulation, and the
luteal phase
• Describe the sequence of events in the uterine cycle,
with reference to menstruation, the proliferative phase,
and the secretory phase
• Describe the control of the ovarian and uterine cycles
by hormones including gonadotropin-releasing hormone
(GnRH), follicle-stimulating hormone (FSH), luteinizing
hormone (LH), estrogen, and progesterone
Structures
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Ovaries – location of egg production
Ova (ovum) - eggs
Oviducts
Uterus
Vagina
Eggs and urine
follow separate
tracts in the
female body
Oogenesis
• Ova development
• Several hundred thousand ova exist at
birth in the ovaries
– Cortical region of follicles of ovaries
• After puberty these ova mature at the
rate of once a month
– Just a few hundred develop over a
lifetime
Oogenesis
• Follicles matures and goes through changes so
that the ovum is now contained in the fluid-filled
space
• Continues until the follicle bulges out from the
ovary structure – GRAAFIAN FOLLICLE
• Ovulation – when the Graafian follicle bursts
releasing the ovum
• Fimbriae direct the ovum to the oviduct
• Oviduct is lined with cilia that direct the ovum
towards the uterus
• Follicular structure that is left behind develops into
glandular tissue called the CORPUS LUTEUM
Uterus
AKA Womb
• Thick-walled, muscular,
pear-shaped organ
• Endometrium
– Inner lining of uterus
with two layers
• Basal layer (adjacent to
muscle & elastic fibers)
• Functional inner lining
(thickness depends on
reproductive cylcle)
Vagina
• Tube that extends from
the cervix to the outside
• Lined with mucosal cells
• Birth Canal
• Organ of copulation
• Clitoris is the female
equivalent to the penis
• Labia – folds of skin that
surround the vaginal
opening
Hormonal Control
• FSH (follicle stimulating hormone)
stimulates ovum maturation
• LH (luteinizing hormone) stimulates
PROGESTERONE and ESTROGEN from
the cells of the follicle
• Progesterone initiates the maturation
of the endometrium lining
• Estrogen is more complex
Estrogen
• Necessary for egg maturation
• Development of secondary sex
characteristics
– Uterine cycle
– Fat and hair distribution
– Growth of the uterus and vagina
– Pelvic growth
– Breast growth (along with progesterone)
Estrogen
• Estrogen appears to have a negative
feedback relationship with the anterior
pituitary because the levels of LH and FSH
decrease when estrogen increases
• Then again when the follicle is mature and
estrogen is at its highest there is a sharp
increase in LH and a slight increase in FSH
• It is thought that estrogen has a positive
feedback relationship with the hypothalamus
– as the increase in LH causes ovulation
Corpus Luteum
• Follicular tissue that remains in the
ovary after ovulation
• Secretes progesterone and estrogen
– Estrogen stimulates the thickening of the
endometrium
– Progesterone stimulates the endometrium
to become secretory
• This prepares the body for fertilization
and pregnancy
Menstruation
• If fertilization doesn’t occur then the corpus
luteum degenerates after approximately 10
days
– Estrogen and progesterone levels drop
– Endometrium that has built up is shed
• Menstruation
– Mainly blood
– AKA menses
– 5 days on average
• During menses the anterior pituitary begins to
release LH and FSH and the cycle begins
again