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PowerPoint® Lecture Slides
prepared by
Barbara Heard,
Atlantic Cape Community
College
CHAPTER
27
The
Reproductive
System: Part
A
© Annie Leibovitz/Contact Press Images
© 2013 Pearson Education, Inc.
Reproductive System
• Primary sex organs (gonads) - testes
and ovaries
– Produce gametes (sex cells ) – sperm & ova
– Secrete steroid sex hormones
• Androgens (males)
• Estrogens and progesterone (females)
• Accessory reproductive organs - ducts,
glands, and external genitalia
© 2013 Pearson Education, Inc.
Reproductive System
• Sex hormones play roles in
– Development and function of reproductive
organs
– Sexual behavior and drives
– Growth and development of many other
organs and tissues
© 2013 Pearson Education, Inc.
Male Reproductive System
• Testes (within scrotum) produce sperm
• Sperm delivered to exterior through
system of ducts
– Epididymis  ductus deferens  ejaculatory
duct  urethra
© 2013 Pearson Education, Inc.
Male Reproductive System
• Accessory sex glands
– Seminal glands
– Prostate
– Bulbo-urethral glands
– Empty secretions into ducts during ejaculation
© 2013 Pearson Education, Inc.
Figure 27.1 Reproductive organs of the male, sagittal view.
Ureter
Peritoneum
Seminal gland
(vesicle)
Ampulla of
ductus deferens
Ejaculatory duct
Rectum
Prostate
Bulbo-urethral gland
Anus
Bulb of penis
Ductus (vas) deferens
© 2013 Pearson Education, Inc.
Epididymis
Testis
Scrotum
Urinary bladder
Prostatic
urethra
Pubis
Intermediate
part of the
urethra
Urogenital
diaphragm
Corpus
cavernosum
Corpus
spongiosum
Spongy
urethra
Glans penis
Prepuce
(foreskin)
External
urethral orifice
The Scrotum
• Sac of skin and superficial fascia
– Hangs outside abdominopelvic cavity
– Contains paired testes
• 3C lower than core body temperature
• Lower temperature necessary for sperm
production
© 2013 Pearson Education, Inc.
The Scrotum
• Temperature kept constant by two sets of
muscles
– Dartos muscle - smooth muscle; wrinkles
scrotal skin; pulls scrotum close to body
– Cremaster muscles - bands of skeletal
muscle that elevate testes
© 2013 Pearson Education, Inc.
Figure 27.2 Relationships of the testis to the scrotum and spermatic cord.
Urinary bladder
Superficial inguinal ring
(end of inguinal canal)
Spermatic cord
Penis
Septum of scrotum
Cremaster muscle
External spermatic
fascia
Superficial fascia
containing dartos
Scrotum muscle
Skin
© 2013 Pearson Education, Inc.
Testicular artery
Ductus (vas)
deferens
Autonomic
nerve fibers
Pampiniform
venous plexus
Epididymis
Tunica vaginalis
(from peritoneum)
Tunica albuginea
of testis
Internal spermatic
fascia
The Testes
• Each surrounded by two tunics
– Tunica vaginalis – outer layer derived from
peritoneum
– Tunica albuginea – inner layer; fibrous
capsule
• Septa divide testis into ~250 lobules, each
containing 1–4 seminiferous tubules site of sperm production
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Seminiferous Tubules
• Interstitial endocrine cells in soft tissue
surrounding seminiferous tubules
• Produce androgens, e.g., testosterone
– Secrete it into interstitial fluid
© 2013 Pearson Education, Inc.
The Testes
• Blood supply
– Testicular arteries arise from abdominal aorta
– Testicular veins arise from pampiniform
venous plexus surrounding each testicular
artery
• Cooler; absorb heat from testicular arteries
• Keep testes cool
• Spermatic cord encloses nerve fibers,
blood vessels, and lymphatics that supply
testes
© 2013 Pearson Education, Inc.
Figure 27.3a Structure of the testis.
Spermatic cord
Blood vessels
and nerves
Ductus (vas)
deferens
Head of epididymis
Testis
Efferent ductule
Seminiferous
tubule
Rete testis
Lobule
Septum
Tunica albuginea
Straight tubule
Body of epididymis
Duct of epididymis
Tail of epididymis
© 2013 Pearson Education, Inc.
Tunica vaginalis
Cavity of
tunica vaginalis
The Penis
• Penis consists of
– Root and shaft that ends in glans penis
– Prepuce, or foreskin—cuff of loose skin
covering glans
– Crura
• Proximal ends of corpora cavernosa surrounded
by ischiocavernosus muscle; anchors penis to
pubic arch
© 2013 Pearson Education, Inc.
Circumcision
• Surgical removal of foreskin
• 60% newborn boys in US circumcised
– 15% in other parts of world
– Some claim medically unnecessary
– Studies show
• 60% reduction in HIV risk
• Reduced risk for other reproductive system
infections
© 2013 Pearson Education, Inc.
The Penis: Internally
• Spongy urethra and three cylindrical
bodies of erectile tissue (spongy network
of connective tissue and smooth muscle
with vascular spaces)
– Corpus spongiosum - surrounds urethra and
expands to form glans and bulb
– Corpora cavernosa - paired dorsal erectile
bodies
• Erection - erectile tissue fills with blood,
causing penis to enlarge and become rigid
© 2013 Pearson Education, Inc.
Figure 27.5 Male reproductive structures.
Ureter
Urinary bladder
Ampulla of ductus deferens
Seminal gland
Prostate
Prostatic urethra
Ejaculatory duct
Orifices of prostatic
ducts
Intermediate part
of the urethra
(membranous urethra)
Urogenital diaphragm
Root of penis
Crus of penis
Bulbo-urethral gland and duct
Bulb of penis
Bulbo-urethral duct opening
Ductus deferens
Corpora cavernosa
Epididymis
Body (shaft)
of penis
Corpus spongiosum
Testis
Section of (b)
Spongy urethra
Glans penis
Prepuce (foreskin)
External urethral orifice
Dorsal vessels
and nerves
Corpora cavernosa
Urethra
Skin
Tunica albuginea of
erectile bodies
Deep arteries
Corpus spongiosum
© 2013 Pearson Education, Inc.
The Male Duct System
• Ducts carry sperm from testes to body
exterior
– Epididymis
– Ductus deferens
– Ejaculatory duct
– Urethra
© 2013 Pearson Education, Inc.
Epididymis
• Head - contains efferent ductules; superior
aspect of testis; body and tail on posterolateral
area of testis
• Duct of the epididymis ~ 6 m in length
– Microvilli (stereocilia) absorb testicular fluid and pass
nutrients to stored sperm
• Nonmotile sperm enter, pass slowly through (~
20 days), become motile; can be stored several
months
• During ejaculation epididymis contracts,
expelling sperm into ductus deferens
© 2013 Pearson Education, Inc.
Ductus Deferens and Ejaculatory Duct
• Ductus deferens (vas deferens) ~ 45 cm
– Passes through inguinal canal to pelvic cavity
– Expands to form ampulla; joins duct of
seminal vesicle to form ejaculatory duct
• Smooth muscle in walls propels sperm
from epididymis to urethra
• Vasectomy - cutting and ligating ductus
deferens; nearly 100% effective form of
birth control
© 2013 Pearson Education, Inc.
Urethra
• Conveys both urine and semen (at
different times)
• Has three regions
– Prostatic urethra – surrounded by prostate
– Intermediate part of the urethra
(membranous urethra) – in urogenital
diaphragm
– Spongy urethra – runs through penis; opens
at external urethral orifice
© 2013 Pearson Education, Inc.
Figure 27.5 Male reproductive structures.
Ureter
Urinary bladder
Ampulla of ductus deferens
Seminal gland
Prostate
Prostatic urethra
Ejaculatory duct
Orifices of prostatic
ducts
Intermediate part
of the urethra
(membranous urethra)
Urogenital diaphragm
Root of penis
Crus of penis
Bulbo-urethral gland and duct
Bulb of penis
Bulbo-urethral duct opening
Ductus deferens
Corpora cavernosa
Epididymis
Body (shaft)
of penis
Corpus spongiosum
Testis
Section of (b)
Spongy urethra
Glans penis
Prepuce (foreskin)
External urethral orifice
Dorsal vessels
and nerves
Corpora cavernosa
Urethra
Skin
Tunica albuginea of
erectile bodies
Deep arteries
Corpus spongiosum
© 2013 Pearson Education, Inc.
The Male Accessory Glands
• Paired seminal glands (seminal
vesicles)
• Paired bulbo-urethral glands
• Prostate
• Produce bulk of semen
– Remainder - sperm from testes
© 2013 Pearson Education, Inc.
Accessory Glands: Seminal Glands
• On posterior bladder surface; smooth
muscle contracts during ejaculation
• Produces viscous alkaline seminal fluid
– Fructose, citric acid, coagulating enzyme
(vesiculase), and prostaglandins
– Yellow pigment fluoresces with UV light
– 70% volume of semen
• Duct of seminal gland joins ductus
deferens to form ejaculatory duct
© 2013 Pearson Education, Inc.
Accessory Glands: Prostate
• Encircles urethra inferior to bladder; size
of peach pit; smooth muscle contracts
during ejaculation
• Secretes milky, slightly acid fluid
– Contains citrate, enzymes, and prostatespecific antigen (PSA)
– Role in sperm activation
– Enters prostatic urethra during ejaculation
• 1/3 semen volume
© 2013 Pearson Education, Inc.
Prostate Disorders
• Prostatitis – inflammatory disorders
– Bacterial infection; acute and chronic; treated
with antibiotics
• Benign prostatic hyperplasia
– May be age-related; distorts urethra; treated
with surgery, microwaves, drugs, balloon
compression, radio-frequency radiation
© 2013 Pearson Education, Inc.
Prostate Disorders
• Prostate cancer
– Second most common cause of cancer death
in males
– Digital exam screening, PSA levels
• Biopsy if abnormal
– Treated with surgery and sometimes
radiation; castration; drugs
– In clinical trials - cryosurgery, chemotherapy,
ultrasound, proton beam therapy
© 2013 Pearson Education, Inc.
Accessory Glands: Bulbo-Urethral Glands
(Cowper's Glands)
• Pea-sized glands inferior to prostate
• Produce thick, clear mucus during sexual
arousal
– Lubricate glans penis
– Neutralize traces of acidic urine in urethra
© 2013 Pearson Education, Inc.
Figure 27.5 Male reproductive structures.
Ureter
Urinary bladder
Ampulla of ductus deferens
Seminal gland
Prostate
Prostatic urethra
Ejaculatory duct
Orifices of prostatic
ducts
Intermediate part
of the urethra
(membranous urethra)
Urogenital diaphragm
Root of penis
Crus of penis
Bulbo-urethral gland and duct
Bulb of penis
Bulbo-urethral duct opening
Ductus deferens
Corpora cavernosa
Epididymis
Body (shaft)
of penis
Corpus spongiosum
Testis
Section of (b)
Spongy urethra
Glans penis
Prepuce (foreskin)
External urethral orifice
Dorsal vessels
and nerves
Corpora cavernosa
Urethra
Skin
Tunica albuginea of
erectile bodies
Deep arteries
Corpus spongiosum
© 2013 Pearson Education, Inc.
Semen
• Milky-white mixture of sperm and
accessory gland secretions
– 2–5 ml semen ejaculated, contains 20–150
million sperm/ml
• Contains fructose for ATP production;
protects and activates sperm; facilitates
sperm movement
• Alkaline  neutralizes acidity of male
urethra and female vagina  enhanced
motility
© 2013 Pearson Education, Inc.
Semen Functions
• Prostaglandins decrease viscosity of mucus in
cervix; stimulate reverse peristalsis in uterus
• Hormone relaxin, enzymes  sperm motility
• Contains ATP for energy
• Suppresses female immune response
• Antibacterial action
• Clotting factors coagulate semen initially to
prevent draining out; then liquefied by
fibrinolysin  sperm begin journey
© 2013 Pearson Education, Inc.
Male Sexual Response
• Erection
– Arterioles normally constricted
– Sexual excitement causes CNS activation of
parasympathetic neurons
–  nitric oxide (NO) release  local vascular
smooth muscle relaxation
–  arterioles dilate  corpora cavernosa
expands, retards venous drainage
–  engorgement of erectile tissues with blood
–  enlargement and stiffening of penis
© 2013 Pearson Education, Inc.
Male Sexual Response
• Ejaculation
– Propulsion of semen from male duct system
– Sympathetic spinal reflex
• Bladder sphincter muscle constricts, preventing
expulsion of urine
• Ducts and accessory glands contract and empty
their contents
• Bulbospongiosus muscles undergo rapid series of
contractions  expulsion of semen at ~ 500 cm/s
(close to 11 mph)
– Ejaculatory event – climax (orgasm)
© 2013 Pearson Education, Inc.
Homeostatic Imbalance
• Erectile dysfunction
– Parasympathetic nerves of penis release too
little NO
– Causes – alcohol, drugs, hormones, blood
vessel or nervous system problems,
incompetent venous valves fail to retain blood
in penis
– New drugs (Viagra, Cialis) potentiate existing
NO effects
© 2013 Pearson Education, Inc.
Spermatogenesis
• Sperm (spermatozoa) production in
seminiferous tubules
• Most body cells have 46 chromosomes diploid chromosomal number (2n)
– Two sets (23 pairs) of chromosomes
• One maternal, one paternal – homologous
chromosomes
– Gametes have 23 chromosomes - haploid
chromosomal number (n)
• Only one member of homologous pair
© 2013 Pearson Education, Inc.
Figure 27.6 Comparison of mitosis and meiosis in a mother cell with a diploid number (2n) of 4.
Mother cell
(before chromosome replication)
Chromosome
replication
Chromosome
replication
2n = 4
MITOSIS
MEIOSIS
Prophase
Replicated
chromosome
Prophase I
Tetrad formed by
synapsis of
replicated homologous
chromosomes
Metaphase
Chromosomes
align at the
metaphase plate
Metaphase I
Tetrads align randomly
at the metaphase plate
Sister chromatids separate
during anaphase
Homologous chromosomes
separate but sister chromatids
remain together during anaphase I
Daughter
cells of
mitosis
2n
Daughter cells
of Meiosis I
2n
Meiosis II
n
MITOSIS
Number of
divisions
Synapsis of
homologous
chromosomes
Daughter cell
number and
genetic
composition
Roles
in the body
© 2013 Pearson Education, Inc.
One, consisting of prophase, metaphase,
anaphase, and telophase.
Does not occur.
No further chromosomal
replication; sister chromatids
separate during anaphase II
n
n
Daughter cells of meiosis II
(usually gametes)
MEIOSIS
Two, each consisting of prophase, metaphase, anaphase, and telophase.
DNA replication does not occur between the two nuclear divisions.
Occurs during prophase I; tetrads form, allowing crossovers.
Two. Each diploid (2n) cell is identical to
the mother cell.
Four. Each haploid (n) cell contains half as many chromosomes as the
mother cell and is genetically different from the mother cell.
For development of multicellular adult from
zygote. Produces cells for growth and tissue
repair as multicellular adult develops. Ensures
genetic makeup of all body cells is constant.
Produces cells for reproduction (gametes). Introduces genetic variability
in the gametes and reduces chromosomal number by half so that when
fertilization occurs, the normal diploid chromosomal number is restored
(in humans, 2n = 46).
n
Figure 27.7 Meiosis.
MEIOSIS I
Interphase cell
Nuclear
envelope Crossover
Spindle
Centriole
pairs
Sister
chromatids
2n = 4
Prophase I
Centromere Prophase events occur, as in mitosis. Additionally,
synapsis occurs: Homologous chromosomes come
together along their length to form tetrads. During
synapsis, the “arms” of homologous chromatids wrap
around each other, forming several crossovers. The
nonsister chromatids trade segments at points of
crossover. Crossover is followed through the diagrams
below.
Chromatin Nuclear envelope
fragments late
in prophase I
Interphase events
As in mitosis, meiosis is preceded
by DNA replication and other
preparations for cell division.
Metaphase I
The tetrads align randomly on the spindle
equator in preparation for anaphase.
Tetrad
Dyad
Chromosomes
uncoil
Nuclear
envelopes
re-form
Cleavage
furrow
Anaphase I
Unlike anaphase of mitosis, the centromeres do not
separate during anaphase I of meiosis, so the sister
chromatids (dyads) remain firmly attached. However, the
homologous chromosomes do separate from each other
and the dyads move toward opposite poles of the cell.
Telophase I
The nuclear membranes re-form around the
chromosomal masses, the spindle breaks down, and
the chromatin reappears as telophase and cytokinesis
end. The 2 daughter cells (now haploid) enter a second
interphase-like period, called interkinesis, before
meiosis II occurs. There is no second replication of DNA
before meiosis II.
MEIOSIS II
Prophase II
Meiosis II begins with the
products of meiosis I (2
haploid daughter cells) and
undergoes a mitosis-like
nuclear division process
referred to as the equational
division of meiosis.
Metaphase II
Anaphase II
After progressing through the
phases of meiosis and
cytokinesis, the product is 4
haploid cells, each genetically
different from the original
mother cell. (During human
Telophase II
and cytokinesis spermatogenesis, the daughter
cells remain interconnected by
cytoplasmic extensions during
the meiotic phases.)
Products of
meiosis:
haploid
daughter cells
© 2013 Pearson Education, Inc.
Spermatogenesis
• Spermatogenic cells give rise to sperm
– Mitosis of spermatogonia (stem cell) forms
two spermatocytes
– Meiosis
• Spermatocytes  secondary spermatocytes 
spermatids
– Spermiogenesis
• Spermatids become sperm
© 2013 Pearson Education, Inc.
Figure 27.8a Spermatogenesis.
Scanning electron micrograph of a
cross-sectional view of a seminiferous
tubule (165x)
© 2013 Pearson Education, Inc.
Figure 27.8c Spermatogenesis.
Tight junction between sustentocytes
Spermatogonium
(stem cell)
Basal lamina
Cytoplasm of
adjacent
sustentocytes
Sustentocyte
cell nucleus
Basal
compartment
Type A daughter cell
remains at basal lamina
as a precursor cell
Type B daughter cell
Primary
spermatocyte
Secondary
spermatocytes
Late spermatids
Cytoplasmic bridge
Spermatozoa
Lumen
of seminiferous
tubule
Adluminal
compartment
Early
spermatids
A portion of the seminiferous tublule wall, showing the
spermatogenic cells surrounded by sustentocytes (colored gold)
© 2013 Pearson Education, Inc.
Mitosis of Spermatogonia
• Spermatogenesis begins at puberty
• Spermatogonia
– Stem cells in contact with epithelial basal
lamina
– Each mitotic division  one type A daughter
cell and one type B daughter cell
© 2013 Pearson Education, Inc.
Mitosis of Spermatogonia
• Type A cells maintain germ cell line at
basal lamina
• Type B cells move toward lumen and
develop into primary spermatocytes
© 2013 Pearson Education, Inc.
Figure 27.8b Spermatogenesis.
Basal lamina
© 2013 Pearson Education, Inc.
Meiosis (early
spermatogenesis)
Spermiogenesis (late
spermatogenesis)
Spermatogenesis
Spermatogonium 2n
(stem cell)
Mitosis
Growth
Enters
meiosis I and
moves to
adluminal
compartment
Meiosis I
completed
Type A daughter cell
remains at basal lamina
as a precursor cell
2n
2n
Type B daughter cell
Primary
spermatocyte
2n
Secondary
spermatocytes
n
n
Meiosis ll
n
n
n
n
n
n
n
n
Early
spermatids
n
n
n
Late spermatids
n
Spermatozoa
Events of spermatogenesis, showing the relative
position of various spermatogenic cells
Figure 27.9 Spermiogenesis: transformation of a spermatid into a functional sperm.
Slide 1
Approximately 24 days
Golgi apparatus
Acrosomal
vesicle
Mitochondria
Acrosome
Nucleus
1
2
Spermatid
nucleus
Centrioles
3
Microtubules
Flagellum
Midpiece Head
Excess
cytoplasm
4
Tail
5
6
© 2013 Pearson Education, Inc.
7
Spermatogenesis
• Takes 64 – 72 days if conditions
hospitable
• Pressure of testicular fluid pushes
immotile sperm into epididymis  motility
and fertilizing power
© 2013 Pearson Education, Inc.
Homeostatic Imbalance
• Infertility
– Gradual decline in male fertility past 50 years
– Xenobiotics (alien molecules) may be cause
• Environmental toxins, PVCs, phthalates,
pesticides, herbicides, compounds with estrogenic
effects, antibiotics, radiation, lead, marijuana
– Also, lack of selenium, excessive alcohol, lack
of specific Ca2+ channel, anatomical
obstructions, hormonal imbalances, oxidative
stress, fevers, hot tubs
© 2013 Pearson Education, Inc.
Hormonal Regulation of Male Reproductive
Function
• Sequence of hormonal regulatory events
involving hypothalamus, anterior pituitary
gland, and testes
– Hypothalamic-pituitary-gonadal (HPG) axis
– Regulates production of gametes and sex
hormones through 3 interacting sets of
hormones
• GnRH indirectly stimulates testes via FSH & LH
• FSH & LH directly stimulate testes
• Testosterone & inhibin – negative feedback on
hypothalamus and anterior pituitary
© 2013 Pearson Education, Inc.
HPG Axis
• Testosterone  sex organ maturation,
development/maintenance secondary sex
characteristics, libido
• Rising testosterone levels  feedback
inhibition on hypothalamus to inhibit GnRH
and on pituitary to inhibit gonadotropin
release
• Inhibin (released when sperm count high) –
inhibits GnRH and FSH release
© 2013 Pearson Education, Inc.
Figure 27.10 Hormonal regulation of testicular function, the hypothalamic-pituitary-gonadal (HPG) axis.
1
GnRH
Anterior
pituitary
Via portal
blood
7
6
Inhibin
FSH
3
2
LH
4
Interstitial
endocrine
cells
Testosterone
Sustentocyte 5
Spermatogenic
cells
Seminiferous
tubule
© 2013 Pearson Education, Inc.
Stimulates
Inhibits
Somatic and
psychological
effects at other
body sites;
maintenance
of secondary sex
characteristics
Slide 1
Adult
Fertilization Birth
100
Puberty
50
0
3
Months
© 2013 Pearson Education, Inc.
6
9
1
10
Age
20
Years
60
Sperm production (% of maximal)
Plasma testosterone level
Figure 27.11 Plasma testosterone and sperm production levels versus age in male humans.
Female Reproductive Anatomy
• Ovaries - female gonads
– Produce female gametes (ova)
– Secrete female sex hormones, estrogen
(estradiol, estrone, estriol) and progesterone
• Accessory ducts include
– Uterine tubes
– Uterus
– Vagina
© 2013 Pearson Education, Inc.
Female Reproductive Anatomy
• Internal genitalia – in pelvic cavity
– Ovaries
– Uterine tubes
– Uterus
– Vagina
• External genitalia
– External sex organs
© 2013 Pearson Education, Inc.
Figure 27.12 Internal organs of the female reproductive system, midsagittal section.
Peritoneum
Uterosacral
ligament
Perimetrium
Rectouterine
pouch
Rectum
Posterior fornix
Cervix
Anterior fornix
Vagina
Anus
Urogenital diaphragm
Greater vestibular
gland
© 2013 Pearson Education, Inc.
Suspensory
ligament
of ovary
Infundibulum
Uterine tube
Ovary
Fimbriae
Uterus
Round ligament
Vesicouterine
pouch
Urinary bladder
Pubic symphysis
Mons pubis
Urethra
Clitoris
External urethral
orifice
Hymen
Labium minus
Labium majus
Figure 27.14 Internal reproductive organs of a female, posterior view.
Suspensory
ligament of ovary
Ovarian
blood
vessels
Broad ligament
• Mesosalpinx
• Mesovarium
• Mesometrium
Uterine (fallopian) tube
Ovarian
ligament
Body of uterus
Ureter
Uterine blood vessels
Isthmus
Uterosacral ligament
Cardinal (lateral cervical)
ligament
Lateral fornix
Cervix
© 2013 Pearson Education, Inc.
Fundus
Lumen (cavity)
of uterus
of uterus
Ovary
Uterine tube
• Ampulla
• Isthmus
• Infundibulum
• Fimbriae
Round ligament of uterus
Wall of uterus
• Endometrium
• Myometrium
• Perimetrium
• Internal os
• Cervical canal
• External os
Vagina
Figure 27.13 Photomicrograph of a mammalian ovary showing follicles in different developmental phases.
Germinal
epithelium
Tunica
albuginea
Cortex
Medulla
Primary
follicles
Secondary
follicle
Antrum of a vesicular
(antral) follicle
© 2013 Pearson Education, Inc.
Female Duct System
• Ducts have no contact with ovary
– Oocyte cast into peritoneal cavity; some lost
there
• Uterine (fallopian) tubes or oviducts
• Uterus
• Vagina
© 2013 Pearson Education, Inc.
Homeostatic Imbalance
• Ectopic pregnancy
– Oocyte fertilized in peritoneal cavity or distal
uterine tube begins developing there
• Normally abort naturally with substantial bleeding
• Pelvic inflammatory disease (PID)
– Spread of infection from reproductive tract to
peritoneal cavity
• May cause scar tissue  infertility
© 2013 Pearson Education, Inc.
Homeostatic Imbalance
• Cervical cancer
– 450,000 women worldwide each year – killing
half
– Most common between 30 – 50
– Risks – frequent cervical inflammations, STIs,
multiple pregnancies
– Papanicolaou (Pap) smear for detection
• Every two years 21 – 30; every year > 30;
discontinue at 65 if negative for 10 years
© 2013 Pearson Education, Inc.
Homeostatic Imbalance
• Pap smear results inconclusive
– Test for human papillomavirus – cause of
most cervical cancers
• Gardasil – three-dose vaccine; protects
against HPV
– Recommended for 11- and 12-year-old girls
© 2013 Pearson Education, Inc.
Vagina
• Layers of wall
– Fibroelastic adventitia
– Smooth muscle muscularis
– Stratified squamous mucosa with rugae
• Dendritic cells in mucosa may provide route for
HIV transmission
• Mucosa near vaginal orifice forms incomplete
partition called hymen – ruptures with
intercourse
• Vaginal fornix - upper end of vagina
surrounding cervix
© 2013 Pearson Education, Inc.
Figure 27.16a The external genitalia (vulva) of the female.
Mons
pubis
Prepuce
of clitoris
Clitoris
(glans)
Vestibule
Labia
majora
Labia
minora
External
urethral
orifice
Hymen
(ruptured)
Anus
Vaginal
orifice
Opening of the duct
of the greater
vestibular gland
© 2013 Pearson Education, Inc.
External Genitalia (Vulva or Pudendum)
• Mons pubis - fatty area overlying pubic
symphysis
• Labia majora - hair-covered, fatty skin
folds
– Counterpart of male scrotum
• Labia minora - skin folds lying within labia
majora
– Join at posterior end of vestibule 
fourchette
– Vestibule - recess within labia minora
© 2013 Pearson Education, Inc.
External Genitalia
• Greater vestibular glands
– Flank vaginal opening
– Homologous to bulbo-urethral glands
– Release mucus into vestibule for lubrication
© 2013 Pearson Education, Inc.
External Genitalia
• Clitoris – anterior to vestibule
– Glans of the clitoris - exposed portion
– Prepuce of the clitoris – hoods glans
– Counterpart of penis
• Perineum
– Diamond-shaped region between pubic arch
and coccyx
– Bordered by ischial tuberosities laterally
© 2013 Pearson Education, Inc.
Figure 27.16b The external genitalia (vulva) of the female.
Clitoris
Labia minora
Labia majora
Anus
Inferior
ramus
of pubis
Pubic symphysis
Body of clitoris,
containing
corpora
cavernosa
Clitoris (glans)
Crus of clitoris
External
urethral orifice
Vaginal orifice
Bulb of
vestibule
Fourchette
© 2013 Pearson Education, Inc.
Greater
vestibular
gland
Mammary Glands
• Modified sweat glands consisting of 15–25
lobes
• Function in milk production
• Areola - pigmented skin surrounding
nipple
• Suspensory ligaments – attach breast to
underlying muscle
• Lobules within lobes contain glandular
alveoli that produce milk
© 2013 Pearson Education, Inc.
Mammary Glands
• Milk  lactiferous ducts  lactiferous
sinuses  open to outside at nipple
• Breast size due to amount of fat deposits
© 2013 Pearson Education, Inc.
Figure 27.17 Structure of lactating mammary glands.
First rib
Skin (cut)
Pectoralis major muscle
Suspensory ligament
Adipose tissue
Lobe
Areola
Nipple
Opening of lactiferous duct
Lactiferous sinus
Lactiferous duct
Lobule containing alveoli
Hypodermis
(superficial fascia)
Intercostal muscles
© 2013 Pearson Education, Inc.
Breast Cancer
• Invasive breast cancer most common
malignancy, second most common cause
of cancer death in U.S. women
• 13% will develop condition
© 2013 Pearson Education, Inc.
Breast Cancer
• Usually arises from epithelial cells of
smallest ducts; eventually metastasize
• Risk factors include
– Early onset of menstruation and late
menopause
– No pregnancies or first pregnancy late in life
– No or short periods of breast feeding
– Family history of breast cancer
• 70% of women with breast cancer have no
known risk factors
© 2013 Pearson Education, Inc.
Breast Cancer
• 10% due to hereditary defects, including
mutations to genes BRCA1 and BRCA2
– 50 – 80% develop breast cancer
– Greater risk of ovarian cancer as well
© 2013 Pearson Education, Inc.
Breast Cancer: Treatment
• Radical mastectomy – removes breast,
all underlying muscles, fascia, associated
lymph nodes
• Lumpectomy – excises only cancerous
lump
• Simple mastectomy – removes only
breast tissue, sometimes some axillary
lymph nodes
• Some have breast reconstruction
© 2013 Pearson Education, Inc.
Figure 27.18 Mammograms.
Malignancy
Mammogram procedure
© 2013 Pearson Education, Inc.
Film of normal breast
Film of breast with tumor
Physiology of the Female Reproductive
System
• Always assumed females total supply of
eggs determined at birth
• New evidence stem cells can arise from
epithelial cells at ovary surface
• May overturn previous assumption
© 2013 Pearson Education, Inc.
Figure 27.19 Events of oogenesis.
Follicle development
in ovary
Meiotic events
Before birth
Oogonium (stem cell)
2n
Follicle cells
Oocyte
Mitosis
Infancy and
childhood
(ovary functionally
inactive)
2n
Primary oocyte
Primordial follicle
2n
Primary oocyte
(arrested in prophase I;
present at birth)
Primordial follicle
Each month from
puberty to menopause
Primary follicle
Primary oocyte (still
arrested in prophase I)
2n
Secondary follicle
Spindle
Vesicular (antral)
follicle
Meiosis I (completed by
one primary oocyte each
month in response to
LH surge)
Secondary oocyte
(arrested in metaphase II)
n
First polar body
Ovulation
Meiosis II of polar body
(may or may not occur)
Polar bodies
(all polar bodies
degenerate)
© 2013 Pearson Education, Inc.
n
Sperm
n
n
n
Second
Ovum
polar body
Ovulated secondary
oocyte
Meiosis II
completed
(only if sperm
penetrates
oocyte)
In absence of fertilization,
ruptured follicle becomes
a corpus luteum and
ultimately degenerates.
Degenerating
corpus luteum
Comparison of Oogenesis and
Spermatogenesis
• Spermatogenesis  4 viable sperm
• Spermatogenesis – error rate of 3-4%
• Oogenesis  1 viable gamete; 3 polar
bodies
• Oogenesis – error rate of 20%
• Unequal divisions ensure oocyte has
ample nutrients for 6-7 day journey to
uterus
• Polar bodies degenerate and die
© 2013 Pearson Education, Inc.
Ovarian Cycle
• Monthly series of events associated with
maturation of egg
• Two consecutive phases (in 28-day cycle)
– Follicular phase - period of follicle growth
(days 1–14)
– Ovulation occurs midcycle
– Luteal phase - period of corpus luteum
activity (days 14–28)
© 2013 Pearson Education, Inc.
Ovarian Cycle
• Only 10 – 15% women have 28-day cycle
• Follicular phase varies
• Luteal phase constant – always 14 days
from ovulation to end of cycle
© 2013 Pearson Education, Inc.
Figure 27.20 Schematic and microscopic views of the ovarian cycle: development and fate of ovarian
follicles.
1 Primordial 2 Primary
follicle
follicles
3a Secondary
Theca folliculi
follicle
3b
3a
3b Late secondary
2
Primary follicle
oocyte
7
Zona pellucida
Antrum
Secondary
4 oocyte
5
6
6
Corona
radiata
Theca
folliculi
Forming
antrum
Secondar
y
oocyte
Zona
pellucida
Antrum
© 2013 Pearson Education, Inc.
6 Corpus luteum
(forms from ruptured
follicle)
5 Follicle ruptures;
secondary oocyte
ovulated
4 Mature vesicular follicle
carries out meiosis I; ready
to be ovulated
Slide 1
PowerPoint® Lecture Slides
prepared by
Barbara Heard,
Atlantic Cape Community
College
CHAPTER
27
The
Reproductive
System: Part
C
© Annie Leibovitz/Contact Press Images
© 2013 Pearson Education, Inc.
Figure 27.21 Regulation of the ovarian cycle.
Hypothalamus
Slide 1
Hypothalamus
GnRH
GnRH
Travels via
portal blood
1
1
FSH
2
3 Slightly
elevated
estrogen and
rising inhibin
levels inhibit
FSH
secretion.
© 2013 Pearson Education, Inc.
Anterior pituitary
LH
2
Thecal cells
2
Androgens
4 Positive
feedback exerted
by large in
estrogen output
by maturing
follicle.
4
6
4
Progesterone
Estrogens
Inhibin
LH surge
Ruptured
5
follicle
6
5
Granulosa
cells
2
Mature vesicular
Inhibin
Convert androgens
follicle
Ovulated
Corpus luteum
to estrogens
secondary
2
oocyte
Estrogens
Late follicular and
Early and
luteal phases
midfollicular phases
Stimulates
Inhibits
Plasma hormone level
Figure 27.22a Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus.
LH
FSH
Fluctuation of gonadotropin levels: Fluctuating levels of pituitary
gonadotropins (follicle-stimulating hormone and luteinizing hormone)
in the blood regulate the events of the ovarian cycle.
© 2013 Pearson Education, Inc.
Figure 27.22b Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus.
Primary Secondary Vesicular Ovulation
follicle follicle
follicle
Follicular
phase
Ovulation
(Day 14)
Corpus
luteum
Degenerating
corpus luteum
Luteal
phase
Ovarian cycle: Structural changes in the ovarian follicles during the
ovarian cycle are correlated with (d) changes in the endometrium of the
uterus during the uterine cycle.
© 2013 Pearson Education, Inc.
The Uterine (Menstrual) Cycle
• Cyclic changes in endometrium in
response to fluctuating ovarian hormone
levels
• Three phases
– Days 1–5 - menstrual phase
– Days 6–14 - proliferative (preovulatory) phase
– Days 15–28 - secretory (postovulatory) phase
(constant 14-day length)
© 2013 Pearson Education, Inc.
Uterine Cycle
• Menstrual phase (Days 1 - 5)
– Ovarian hormones at lowest levels
– Gonadotropins beginning to rise
– Stratum functionalis shed; menstrual flow
(blood and tissue) 3 - 5 days
– By day 5 growing ovarian follicles produce
more estrogen
© 2013 Pearson Education, Inc.
Uterine Cycle
• Proliferative phase (Days 6 - 14)
– Rising estrogen levels prompt generation of
new stratum functionalis layer; increased
synthesis of progesterone receptors in
endometrium; glands enlarge and spiral
arteries increase in number
– Normally thick, sticky cervical mucus thins in
response to rising estrogen (allows sperm
passage)
– Ovulation occurs at end of proliferative phase
© 2013 Pearson Education, Inc.
Plasma hormone level
Figure 27.22c Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus.
Estrogens
Progesterone
Fluctuation of ovarian hormone levels: Fluctuating levels of ovarian
hormones (estrogens and progesterone) cause the endometrial changes
of the uterine cycle. The high estrogen levels are also responsible for the
LH/FSH surge in (a).
© 2013 Pearson Education, Inc.
Figure 27.22d Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus.
Endometrial
glands
Blood vessels
Menstrual
flow
Functional
layer
Basal layer
Days 1
5
Menstrual
phase
10
Proliferative
phase
15
25
20
Secretory
phase
28
The three phases of the uterine cycle:
• Menstrual: The functional layer of the endometrium is shed.
• Proliferative: The functional layer of the endometrium is rebuilt.
• Secretory: Begins immediately after ovulation. Enrichment of the blood
supply and glandular secretion of nutrients prepare the endometrium to
receive an embryo.
Both the menstrual and proliferative phases occur before ovulation, and
together they correspond to the follicular phase of the ovarian cycle. The
secretory phase corresponds in time to the luteal phase of the ovarian cycle.
© 2013 Pearson Education, Inc.
Effects of Estrogens
• Promote oogenesis and follicle growth in
ovary
• Exert anabolic effects on female
reproductive tract
• Support rapid but short-lived growth spurt
at puberty
© 2013 Pearson Education, Inc.
Effects of Estrogens
• Induce secondary sex characteristics
– Growth of breasts
– Increased deposit of subcutaneous fat (hips
and breasts)
– Widening and lightening of pelvis
© 2013 Pearson Education, Inc.
Effects of Estrogens
• Metabolic effects (not true secondary sex
characteristics)
– Maintain low total blood cholesterol and high
HDL levels
– Facilitate calcium uptake
© 2013 Pearson Education, Inc.
Effects of Progesterone
• Progesterone works with estrogen to
establish and regulate uterine cycle
• Promotes changes in cervical mucus
• Effects of placental progesterone during
pregnancy
– Inhibits uterine motility
– Helps prepare breasts for lactation
© 2013 Pearson Education, Inc.
Sexually Transmitted Infections (STIs)
• Also called sexually transmitted diseases
(STDs) or venereal diseases (VDs)
• U.S. – highest rates of infection among
developed countries
• Latex condoms help prevent spread
• Single most important cause of
reproductive disorders
© 2013 Pearson Education, Inc.
Gonorrhea
• Commonly called "the clap"
• Bacterial infection of mucosae of
reproductive and urinary tracts
• Spread by contact with genital, anal, and
pharyngeal mucosae
• Number of cases in U.S. declining
© 2013 Pearson Education, Inc.
Gonorrhea
• Signs and symptoms
– Males
• Urethritis, painful urination, discharge of pus
– Females
• 20% display no signs or symptoms
• Abdominal discomfort, vaginal discharge, or
abnormal uterine bleeding
• Can result in pelvic inflammatory disease and
sterility
• Treatment - antibiotics, but resistant
strains becoming prevalent
© 2013 Pearson Education, Inc.
Syphilis
• Bacterial infection transmitted sexually or
contracted congenitally
– Infected fetuses stillborn or die shortly after
birth
• Infection asymptomatic for 2–3 weeks
• Painless chancre appears at site of
infection; disappears in few weeks
© 2013 Pearson Education, Inc.
Syphilis
• If untreated, secondary signs appear
several weeks later for 3–12 weeks, then
disappear
– Pink skin rash, fever, and joint pain
• Latent period may or may not progress to
tertiary syphilis, characterized by gummas
(lesions of CNS, blood vessels, bones,
and skin)
• Treatment - penicillin
© 2013 Pearson Education, Inc.
Chlamydia
• Most common bacterial STI in United States
• Responsible for 25–50% of all diagnosed cases
of pelvic inflammatory disease
• Symptoms - urethritis; penile and vaginal
discharges; abdominal, rectal, or testicular pain;
painful intercourse; irregular menses
• Can cause arthritis and urinary tract infections in
men; sterility in women; newborns contract in
birth canal  trachoma (painful eye infection),
respiratory tract inflammation
• Treatment - tetracycline
© 2013 Pearson Education, Inc.
Trichomoniasis
• Most common curable STI in active young
women in U.S.
• Parasitic infection; easily, inexpensively
treated
• Yellow-green vaginal discharge with strong
odor; some symptomless
© 2013 Pearson Education, Inc.
Viral Infections
• Genital warts
– Caused by human papillomavirus (HPV)
– Second most common STI in United States
– Increased risk of cancers in infected body
regions
• Linked to 80% cases of invasive cervical cancer;
most strains do not cause cancer
– Treatment difficult; controversial
© 2013 Pearson Education, Inc.
Viral Infections
• Genital herpes
– Caused by herpes simplex virus 2
– Characterized by latent periods and flare-ups
• Congenital herpes can cause malformations of
fetus
– Treatment - acyclovir and other antiviral drugs
© 2013 Pearson Education, Inc.
Figure 27.24a Development of homologous structures of the external genitalia in both sexes.
Genital
tubercle
Urethral fold
Labioscrotal
swelling
Anus
Tail (cut)
Urethral groove
Sexually indifferent
stage
© 2013 Pearson Education, Inc.
Figure 27.24b Development of homologous structures of the external genitalia in both sexes.
Approximately 5 weeks
Glans penis
Urethral folds
Labioscrotal
swellings
(scrotum)
Anus
Glans penis
Penis
Scrotum
Anus
Male development
© 2013 Pearson Education, Inc.
Figure 27.24c Development of homologous structures of the external genitalia in both sexes.
Approximately 5 weeks
Glans clitoris
Urogenital
sinus
Labioscrotal
swellings
(labia majora)
Urethral
folds
(labia
minora)
Anus
Glans clitoris
Labia majora
Labia
minora
Anus
© 2013 Pearson Education, Inc.
Female development
Development Aspects: Descent of the
Gonads
• About two months before birth
– Testosterone stimulates migration of testes
toward scrotum
• Gubernaculum - fibrous cord from each
testis to scrotum or from ovary to labium
majus; guides descent
• Ovaries also descend, but stopped by
broad ligament at pelvic brim
© 2013 Pearson Education, Inc.
Figure 27.23 Development of the internal reproductive organs.
Mesonephros
Mesonephric
(Wolffian) duct
Gonadal ridge
Paramesonephric
(Müllerian) duct
Metanephros
(kidney)
Cloaca
5- to 6-week embryo:
sexually indifferent stage
Testes
Efferent ductules
Ovaries
Epididymis
Paramesonephric
duct forming the
uterine tube
Paramesonephric
duct (degenerating)
Mesonephric duct
(degenerating)
Mesonephric duct
forming the ductus
deferens
Fused
paramesonephric
ducts forming
the uterus
Urinary bladder
Seminal gland
Urinary bladder
(moved aside)
Urogenital sinus
forming the urethra
and lower vagina
Urogenital sinus
forming the urethra
7- to 8-week male
8- to 9-week female
Uterine tube
Urinary bladder
Seminal gland
Ovary
Prostate
Bulbo-urethral gland
Uterus
Ductus deferens
Urethra
Urinary bladder
(moved aside)
Efferent ductules
Vagina
Epididymis
Urethra
Testis
Hymen
Vestibule
Penis
At birth: male development
© 2013 Pearson Education, Inc.
At birth: Female development
© 2013 Pearson Education, Inc.
Development Aspects: Puberty
• FSH and LH elevated at birth but drop and
remain low during prepubertal years
• Reproductive organs grow to adult size
and become functional – puberty
• Occurs in response to rising levels of
gonadal hormones
• Secondary sex characteristics appear
• Earliest time that reproduction is possible
© 2013 Pearson Education, Inc.
Menopause
• Has occurred when menses have ceased
for an entire year
• No equivalent to menopause in males
– Males continue to produce sperm well into
eighth decade of life, though numbers and
motility decrease
© 2013 Pearson Education, Inc.
Menopause
• Declining estrogen levels 
– Atrophy of reproductive organs and breasts
– Irritability and depression in some
– Hot flashes as skin blood vessels undergo
intense vasodilation
– Gradual thinning of skin and bone loss
– Increased total blood cholesterol levels and
falling HDL
© 2013 Pearson Education, Inc.
Menopause
• Treatment with estrogen-progesterone
preparations given for years
– Women's Health Initiative research reported
increased risk of heart disease (51%),
invasive breast cancer (24%), stroke (31%),
dementia (risk doubled)
– Smallest does for shortest time alright to
reduce symptoms if no breast cancer or
mutated BRCA gene
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
Sperm
• Major regions
– Head - genetic region; nucleus and helmetlike
acrosome containing hydrolytic enzymes that
enable sperm to penetrate egg
– Midpiece - metabolic region; mitochondria 
ATP to move tail
– Tail - locomotor region; flagellum
© 2013 Pearson Education, Inc.
Role of Sustentocytes
• Large supporting cells (Sertoli cells)
– Extend through wall of tubule and surround
developing cells
– Provide nutrients and signals to dividing cells
– Move cells along to lumen
– Secrete testicular fluid into lumen for sperm
transport
– Phagocytize faulty germ cells and excess
cytoplasm
– Produce chemical mediators to regulate
spermatogenesis
© 2013 Pearson Education, Inc.
Mechanism and Effects of Testosterone
Activity
• Testosterone
– Synthesized from cholesterol
– Transformed to exert its effects on some
target cells
• Dihydrotestosterone (DHT) in prostate
• Estradiol in some neurons in brain
© 2013 Pearson Education, Inc.
Ovaries
• Held in place by several ligaments
– Ovarian ligament - anchors ovary medially to
uterus
– Suspensory ligament - anchors ovary
laterally to pelvic wall
– Mesovarium - suspends ovary
• Suspensory ligament and mesovarium
part of broad ligament – supports uterine
tubes, uterus, and vagina
© 2013 Pearson Education, Inc.
Breast Cancer: Diagnosis
• Early detection via self-examination and
mammography
– X-ray examination
– American Cancer Society recommends
screening every year for women 40 and over
– U.S. Prevention Services Task Force on
Breast Cancer Screening recommends 50
and over
© 2013 Pearson Education, Inc.
Breast Cancer: Treatment
• Treatment depends upon characteristics of
lesion
– Radiation; chemotherapy; surgery, often
followed by radiation or chemotherapy to
destroy stray cells
– Drugs for estrogen-responsive cancers
• Trastuzumab – for aggressive cancer cells
• Tamoxifen – improves outcome for premenopausal
women with early- or late-stage
• Letrozole – reduces recurrence
© 2013 Pearson Education, Inc.
Developmental Aspects: Determination of
Genetic Sex
• Of 46 chromosomes in fertilized egg, two
(one pair) are sex chromosomes
• Two sex chromosomes – X chromosome
(large); Y chromosome (quite small)
• Females are XX; each ovum always has
an X chromosome
• Males are XY, so ~50% of sperm contain
X, ~50% contain Y
© 2013 Pearson Education, Inc.
Developmental Aspects: Determination of
Genetic Sex
• X egg + X sperm  XX (female offspring)
• X egg + Y sperm  XY (male offspring)
• The SRY gene on Y chromosome initiates
testes development and maleness
© 2013 Pearson Education, Inc.
Developmental Aspects: Sexual
Differentiation
• Sexually indifferent stage
– Gonads begin development in fifth week as gonadal
ridges
– Paramesonephric (Müllerian) ducts (future female
ducts) form lateral to mesonephric (Wolffian) ducts
(future male ducts); sexually indifferent stage embryo could develop into male or female
– Primordial germ cells migrate to gonadal ridges to
provide germ cells destined to become
spermatogonia or oogonia
• Gonads begin development in seventh week in
males, eighth week in females
© 2013 Pearson Education, Inc.
Developmental Aspects: Development of
External Genitalia
• Genital tubercle  penis of male; clitoris
of female
• Urethral fold  spongy urethra of male;
labia minora of female
• Labioscrotal swellings  scrotum of
male: labia majora of female
• If testosterone absent, all embryos
develop into females
© 2013 Pearson Education, Inc.