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Chapter 28
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Female Reproductive System
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Reproductive Anatomy
*Puberty and Menopause
*Oogenesis and the Sexual Cycle
Female Sexual Response
Pregnancy and Childbirth
Lactation
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Female Reproductive System
• Produce and
deliver
gametes
• Provide
nutrition and
room for fetal
development
• Give birth
• Nourish infant
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*Ovary
• Produces eggs and hormones
– almond-shaped, 3 cm x 1.5 cm x 1 cm
– tunica albuginea capsule like on testes
– cortex produces gametes; medulla holds vessels
• Each egg develops in its own fluid-filled follicle
and is released by ovulation
• Ligaments
– attached to uterus by ovarian ligament
– attached to pelvic wall by suspensory ligament
• contains ovarian artery, vein and nerves
– anchored to broad ligament by mesovarium
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*Anatomy of Ovary
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Uterine (Fallopian) Tubes
• 10 cm long, muscular tube
lined with ciliated cells
• Major portions
– narrow isthmus near uterus
– body (ampulla): middle
portion
– flares distally into
infundibulum
with fimbriae
• Enclosed in superior
margin of broad
ligament (mesosalpinx)
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Uterus
• Thick-walled, pear-shaped muscular chamber that opens
into vagina and tilts forward over urinary bladder
– internal and external os of cervical canal
– openings into uterine tubes in two upper corners
• Domed fundus above body of organ
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Histology of Uterine Wall
• Perimetrium - external serosa layer
• Myometrium - middle muscular layer
– 1.25 cm thick in nonpregnant uterus
– smooth muscle
• produces labor contractions, expels fetus
• Endometrium
– simple columnar epithelium with thick layer
compound tubular glands
• stratum functionalis – superficial, shed each period
• stratum basalis - deep layer, regenerates a new
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stratum functionalis with each menstrual cycle
Normal/Abnormal PAP Smears
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Breast Cancer
• 1 out of 8 American women
• Tumors begin with cells from mammary ducts
– may metastasize by lymphatics
• Symptoms may include palpable lump, skin
puckering, skin texture and drainage from nipple
• Most breast cancer is nonhereditary
– some stimulated by estrogen
• Risk factors include
– aging, ionizing radiation, carcinogenic chemicals,
alcohol, smoking and fat intake
– 70% lack risk factors
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*Puberty
• Begins at age 9-10 (US)
• Triggered by rising levels of GnRH
– stimulates anterior lobe of pituitary to produce
• follicle-stimulating hormone (FSH)
• luteinizing hormone (LH)
• Follicles develop and begin to secrete
estrogen and progesterone
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*Puberty
• Thelarche - development of breasts
• Pubarche - growth of pubic and axillary hair;
apocrine and sebaceous glands
• Menarche - first menstrual period
– requires at least 17% body fat in teenager,
22% in adult
• leptin stimulates gonadotropin secretion
• improved nutrition ( body fat) has lowered avg.
age of onset to 12
• Female hormones secreted cyclically and
in sequence
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Climacteric
• Midlife change in hormone secretion
– due to age related depletion of follicles
– occurs with menopause (cessation of
menstruation); average age of 52
• Results
– atrophy of uterus, vagina and breasts
– skin becomes thinner, bone mass declines,
and risks of cardiovascular disease
increase
– hot flashes (sudden dilation of cutaneous
arteries) occur several times a day
• HRT = hormone replacement therapy
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*Oogensis and Sexual Cycle
• Reproductive cycle - events occurring
between fertilization and birth
• Sexual cycle - events recurring every
month when pregnancy does not occur
– ovarian cycle = events in ovaries
– menstrual cycle = parallel changes in uterus
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*Oogenesis
• Monthly event produces haploid egg by meiosis
• Embryonic development of ovary
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female germ cells arise from yolk sac
differentiate into oogonia, multiply
transform into primary oocytes - early meiosis I
most degenerate (atresia) by childhood
by puberty 400,000 oocytes remain
• FSH stimulates completion of meiosis I,
produces secondary oocyte and 1st polar body
– proceeds to meiosis II and ceases until fertilization
– after fertilization , releases 2nd polar body
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*Oogenesis and Follicle
Development
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*Sexual Cycle
• Averages 28 days, ranges from 20 to 45
• Hormone cycle: hierarchy of control
– hypothalamus pituitary  ovaries  uterus
• Follicular phase (2 weeks)
– menstruation occurs during first 3 to 5 days of cycle
– uterus replaces lost endometrium and follicles grow
• Luteal phase (2 weeks)
– corpus luteum stimulates endometrial thickening
– endometrium lost without pregnancy
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*Ovarian Cycle - Follicular Phase
• Menstruation (day 1) to ovulation(14) (variable)
• Difficult to predict date of ovulation
• Contains menstrual and preovulatory phases 28-18
*Ovarian Cycle - Preantral Phase
• Discharge of menstrual fluid (days 1-5)
• Before follicle develops antrum
– primordial and primary follicles
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*Ovarian Cycle - Antral Phase
• Day 6 to 14, one dominant follicle advances to
mature (graafian) follicle; secretes estrogen
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*Ovarian Cycle - Ovulation
• Mature follicle ruptures, releases oocyte
influenced by LH
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Histology of Ovarian Follicles
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*Pituitary-Ovarian Axis
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*Ovarian Cycle - Luteal Phase
• Corpus luteum - forms from ruptured follicle,
under influence of LH; secretes progesterone
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*Menstrual Cycle - Proliferative
Phase
• Day 6-14 rebuild endometrial tissue
– mitosis occurs in stratum basalis
– result of estrogen from developing follicles
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*Menstrual Cycle - Secretory Phase
• Further thickening of endometrium due to
secretion and fluid accumulation -- not mitosis
• Due to progesterone stimulation of glands
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*Menstrual Cycle Premenstrual
Phase
• Involution of corpus luteum, progesterone falls
– spiral arteries constrict causes endometrial ischemia
– stratum functionalis sloughs
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*Menstrual Cycle - Menstrual Phase
• Blood, serous fluid and endometrial tissue are
discharged
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Pregnancy and Childbirth
• Gestation (pregnancy)
– lasts an average of 266 days from conception
to childbirth
– gestational calendar measured from first day
of the woman’s last menstrual period (LMP)
• Birth predicted 280 days from LMP
– 3 three month intervals called trimesters
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Prenatal Development
• Age based terminology
– blastocyst is less than 2 weeks old
– embryo is from 2 to 8 weeks old
– fetus is 9 weeks to birth
– neonate - newborn to 6 weeks
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*Hormones of Pregnancy
• HCG (human chorionic gonadotropin)
– secreted by trophoblast within 9 days of
conception
– prevents involution of corpus luteum
• Estrogens
– increases to 30 times normal before birth
– corpus luteum is source for first 12 weeks until
placenta takes over
– causes uterine, mammary duct and breast
enlargement
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*Hormones of Pregnancy
• Progesterone
– secreted by placenta and corpus luteum
– suppresses secretion of FSH and LH
preventing follicular development
– prevents menstruation, thickens endometrium
– stimulates development of acini in breast
• HCS (human chorionic somatomammotropin)
– secreted from placenta in direct proportion to
its size
–  mother’s glucose usage and  release of
fatty acids
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*Hormones of Pregnancy
• Aldosterone secretion rises
– fluid retention  mother’s blood volume
• Endocrine organs
– thyroid gland increases 50% in size
•  BMR of mother
– parathyroid glands enlarge
• stimulate osteoclasts to release additional calcium
from mother’s bones
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*Hormone Levels and Pregnancy
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*Labor Contractions
• Self-amplifying cycle of stretch and
contraction
– positive feedback cycles increase contractions
• cervical stretching  oxytocin secretion 
uterine contraction  repeat
• reflex arc from uterus  spinal cord 
abdominal skeletal muscles
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*Mammary Gland Development
• Lactation
– synthesis and ejection of milk from mammary
glands in breast
• Ducts grow and branch
– due to high estrogen levels in pregnancy
• Followed by budding and development of
acini at the ends of the ducts
– due to progesterone
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*Colostrum and Milk Synthesis
• Colostrum forms in late pregnancy
– similar to breast milk; contains 1/3 less fat,
thinner
– first 1 to 3 days after birth
– contains IgA protection from gastroenteritis
• Synthesis is promoted by prolactin (from
pituitary)
– synthesis of hormone begins 5 weeks into
pregnancy, by full term it is 20x normal level
– steroid hormones from placenta oppose it until
birth
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*Colostrum and Milk Synthesis
• At birth, prolactin secretion drops, but 
20 times after nursing
– without nursing, milk production stops in 1
week
• 5-10% of women become pregnant while
nursing
– inhibition of GnRH and reduced ovarian
cycling
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*Milk Ejection
• Controlled by a neuroendocrine reflex
– infant’s suckling stimulates sensory
receptors in nipple, signaling hypothalamus
and posterior pituitary to release oxytocin
– oxytocin stimulates myoepithelial cells
• Myoepithelial cells surround secretory
cells in acinus
– contract to squeeze milk into duct
• milk flow within 30-60 seconds after suckling
begins
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Contraceptive Devices
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