ovaries: female gonads
TRANSCRIPT
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Female Reproductive Anatomy
• Ovaries: female gonads
• Produce female gametes (ova)
• Secrete female sex hormones (estrogen and
progesterone)
• Accessory ducts include
• Uterine tubes
• Uterus
• Vagina
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Female Reproductive Anatomy
• Internal genitalia
• Ovaries
• Uterine tubes
• Uterus
• Vagina
• External genitalia
• The external sex organs
Figure 27.10
Peritoneum
Infundibulum
Uterine tubeOvary
UterusRound ligament
Vesicouterine pouch
Urinary bladderPubic symphysisMons pubis
UrethraClitoris
External urethralorificeHymenLabium minusLabium majus
Suspensoryligament of ovary
Uterosacralligament
PerimetriumRectouterinepouch
RectumPosterior fornixCervixAnterior fornixVagina
Anus
Urogenital diaphragm
Greater vestibular(Bartholin’s) gland
Fimbriae
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Ovaries
• Held in place by several ligaments
• Ovarian ligament: anchors ovary medially to the uterus
• Suspensory ligament: anchors ovary laterally to the pelvic wall
• Mesovarium: suspends the ovary
• Broad ligament: supports the uterine tubes, uterus, and vagina; also contains the suspensory ligament and the mesovarium
Figure 27.12a
Vagina
External os
Cervical canal
Internal os
Wall of uterus
Perimetrium
Myometrium
Endometrium
Round ligament of uterus
Uterine
tube
Infundibulum
Fimbriae
Isthmus
Ampulla
Lumen (cavity)
of uterus
Suspensory
ligament of ovary Uterine (fallopian) tube
Ovarian blood
vessels
MesosalpinxMesovarium
Broad
ligament Mesometrium
Ovary
Ovarian ligamentBody of uterus
UreterUterine blood vesselsIsthmus
Uterosacral ligamentLateral cervical
(cardinal) ligamentLateral fornixCervix
(a)
Fundus
of uterus
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Ovaries
• Blood supply: ovarian arteries and the ovarian
branch of the uterine artery
• Surrounded by a fibrous tunica albuginea
• Two poorly defined regions
• Cortex: ovarian follicles
• Medulla: large blood vessels and nerves
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Ovaries
• Follicle
• Immature egg (oocyte) surrounded by
• Follicle cells (one cell layer thick)
• Granulosa cells (when more than one layer
is present)
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Follicles
• Several stages of development
• Primordial follicle: squamouslike follicle cells + oocyte
• Primary follicle: cuboidal or columnar follicle cells + oocyte
• Secondary follicle: two or more layers of granulosa cells + oocyte
• Late secondary follicle: contains fluid-filled space between granulosa cells; coalesces to form a central antrum
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Ovaries
• Vesicular (Graafian) follicle
• Fluid-filled antrum forms; follicle bulges from
ovary surface
• Ovulation
• Ejection of the oocyte from the ripening follicle
• Corpus luteum develops from ruptured follicle
after ovulation
Figure 27.11a
Medulla
Tunica
albuginea
Germinal
epithelium
Cortex
Oocyte Granulosa cells
Late secondary follicle
Antrum
Primary
follicles
Oocyte
Zona
pellucidaTheca
folliculi
Ovulated
oocyte
Mesovarium and
blood vessels
Vesicular
(Graafian)
follicle
Corona
radiata
Developing
corpus luteum
Corpus luteum
Ovarian
ligament
Degenerating corpus
luteum (corpus
albicans)
(a) Diagrammatic view of an ovary sectioned to reveal the follicles in its interior
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Female Duct System
• Uterine (fallopian) tubes or oviducts
• Uterus
• Vagina
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Uterine Tubes
• Ampulla
• Distal expansion with infundibulum near ovary
• Usual site of fertilization
• Ciliated fibriae of infundibulum create currents
to move oocyte into uterine tube
• Isthmus: constricted region where tube joins
uterus
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Uterine Tubes
• Oocyte is carried along by peristalsis and
ciliary action
• Nonciliated cells nourish the oocyte and the
sperm
• Mesosalpinx: mesentery that supports the
uterine tubes
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Uterus
• Body: major portion
• Fundus: rounded superior region
• Isthmus: narrowed inferior region
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Uterus
• Cervix: narrow neck, or outlet; projects into
the vagina
• Cervical canal communicates with the
• Vagina
• Uterine body
• Cervical glands secrete mucus that blocks
sperm entry except during midcycle
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Supports of the Uterus
• Mesometrium—lateral support: portion of the
broad ligament
• Lateral cervical (cardinal) ligaments: from the
cervix and superior part of the vagina to the
walls of the pelvis
• Uterosacral ligaments secure uterus to the
sacrum
• Round ligaments bind to the anterior wall
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Peritoneal Pouches
• Sacs of peritoneum exist around the uterus
• Vesicouterine pouch is between bladder and
uterus
• Rectouterine pouch is between rectum and
uterus
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Uterine Wall
• Three layers
1. Perimetrium: serous layer (visceral
peritoneum)
2. Myometrium: interlacing layers of smooth
muscle
3. Endometrium: mucosal lining
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Endometrium
• Stratum functionalis (functional layer)
• Changes in response to ovarian hormone
cycles
• Is shed during menstruation
• Stratum basalis (basal layer)
• Forms new functionalis after menstruation
• Unresponsive to ovarian hormones
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Uterine Vascular Supply
• Uterine arteries: arise from internal iliacs
• Spasms of spiral arteries leads to shedding of stratum functionalis
Figure 27.13b
Lumen of uterus
Uterine glands
Smooth muscle fibers
Straight artery
Radial artery
Arcuate artery
Uterine artery
Endometrial vein
Capillaries
Venous sinusoids
Epithelium
Spiral (coiled) artery
Lamina propria of
connective tissue
(b)
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Vagina
• Birth canal and organ of copulation
• Extends between the bladder and the rectum
from the cervix to the exterior
• Urethra embedded in the anterior wall
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Vagina
• Layers of wall
1. Fibroelastic adventitia
2. Smooth muscle muscularis
3. Stratified squamous mucosa with rugae
• Mucosa near the vaginal orifice forms an incomplete partition called the hymen
• Vaginal fornix: upper end of the vagina surrounding the cervix
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Mammary Glands
• Modified sweat glands consisting of 15–25
lobes
• Areola: pigmented skin surrounding the nipple
• Suspensory ligaments: attach the breast to
underlying muscle
• Lobules within lobes contain glandular alveoli
that produce milk
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Mammary Glands
• Milk
• lactiferous ducts
• lactiferous sinuses
• open to the outside at the nipple
Figure 27.15
Skin (cut)
Pectoralis major muscle
Suspensory ligament
Adipose tissue
Lobe
Areola
Nipple
Opening of
lactiferous duct
Lactiferous sinus
Lactiferous duct
Hypodermis
(superficial fascia)
Intercostal muscles
Lobule containing
alveoli
(a) (b)
First rib
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Breast Cancer
• Usually arises from the epithelial cells of small ducts
• Risk factors include:
• Early onset of menstruation and late menopause
• No pregnancies or first pregnancy late in life
• Family history of breast cancer
• 10% are due to hereditary defects, including mutations to the genes BRCA1 and BRCA2
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Breast Cancer: Detection and Treatment
• 70% of women with breast cancer have no
known risk factors
• Early detection via self-examination and
mammography
• Treatment depends upon the characteristics
of the lesion:
• Radiation, chemotherapy, and surgery
followed by irradiation and chemotherapy
Figure 27.16
(b) Film of normal breast
(a) Mammogram procedure
(c) Film of breast with tumor
Malignancy
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Oogenesis
• Production of female gametes
• Begins in the fetal period
• Oogonia (2n ovarian stem cells) multiply by
mitosis and store nutrients
• Primary oocytes develop in primordial follicles
• Primary oocytes begin meiosis but stall in
prophase I
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Oogenesis
• Each month after puberty, a few primary
oocytes are activated
• One is selected each month to resume
meiosis I
• Result is two haploid cells
• Secondary oocyte
• First polar body
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Oogenesis
• The secondary oocyte arrests in metaphase II
and is ovulated
• If penetrated by sperm the second oocyte
completes meiosis II, yielding
• Ovum (the functional gamete)
• Second polar body
Figure 27.17
Meiotic events Follicle development
in ovaryBefore birth
Infancy and
childhood
(ovary inactive)
Primary oocyte
Primary oocyte (still
arrested in prophase I)
Vesicular (Graafian)
follicle
Primary follicle
Primordial follicle
Primordial follicle
Oocyte
Ovulated secondary
oocyte
In absence of
fertilization, ruptured
follicle becomes a
corpus luteum and
ultimately degenerates.Degenating
corpus luteum
Secondary follicle
Primary oocyte
(arrested in prophase I;
present at birth)
Oogonium (stem cell)
Each month from
puberty to
menopause
Meiosis I (completed
by one primary oocyte
each month in response
to LH surge)
First polar body
Mitosis
Growth
Meiosis II of polar
body (may or may
not occur)
Polar bodies
(all polar bodies
degenerate)
OvumSecond
polar body
Meiosis IIcompleted(only if spermpenetration occurs)
Sperm
Ovulation
Secondary oocyte
(arrested in
metaphase II)
Follicle cells
Spindle
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Ovarian Cycle
• Monthly series of events associated with the
maturation of an egg
• Two consecutive phases (in a 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)
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Male Reproductive System
• Primary sex organs (gonads): testes and
ovaries
• Produce sex cells (gametes)
• Secrete steroid sex hormones
• Androgens (males)
• Estrogens and progesterone (females)
• Accessory reproductive organs: ducts, glands,
and external genitalia
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Reproductive System
• Sex hormones play roles in
• Development and function of the reproductive
organs
• Sexual behavior and drives
• Growth and development of many other
organs and tissues
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Male Reproductive System
• Testes (within the scrotum) produce sperm
• Sperm are delivered to the exterior through a
system of ducts
• Epididymis, ductus deferens, ejaculatory duct,
and the urethra
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Male Reproductive System
• Accessory sex glands: seminal vesicles,
prostate, and bulbourethral glands
• Empty secretions into the ducts during
ejaculation
Figure 27.1
PeritoneumSeminalvesicle
Ampulla ofductus deferens
Ejaculatoryduct
RectumProstateBulbourethralgland
AnusBulb of penis
Epididymis
Ureter
Urinary bladderProstaticurethra
Pubis
Membranousurethra
Urogenital
diaphragm
Corpuscavernosum
Corpusspongiosum
Glans penis
PrepuceExternalurethral orifice
Spongy urethra
Testis
Scrotum
Ductus (vas)deferens
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The Scrotum
• Sac of skin and superficial fascia
• Hangs outside the abdominopelvic cavity
• Contains paired testes
• 3 C lower than core body temperature
(temperature necessary for sperm
production)
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The Scrotum
• Temperature is kept constant by two sets of
muscles
• Smooth muscle that wrinkles scrotal skin
(dartos muscle)
• Bands of skeletal muscle that elevate the
testes (cremaster muscles)
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The Testes
• Each is surrounded by two tunics
• Tunica vaginalis, derived from peritoneum
• Tunica albuginea, the fibrous capsule
• Septa divide the testis into 250–300 lobules,
each containing 1–4 seminiferous tubules
(site of sperm production)
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The Testes
• Sperm are conveyed through
• Seminiferous tubules
• Tubulus rectus
• Rete testis
• Efferent ductules
• Epididymis
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The Testes
• Blood supply comes from the testicular
arteries and testicular veins
• Spermatic cord encloses nerve fibers, blood
vessels, and lymphatics that supply the testes
Figure 27.3a
Head of epididymis
Body of epididymis
Tail of epididymis
Efferent ductule
Rete testis
Straight tubule
Duct of epididymis
Ductus (vas)
deferens
Lobule
Testis
Septum
Tunica albuginea
Tunica vaginalis
Cavity of
tunica vaginalis
Spermatic cord
Seminiferous
tubule
Blood vessels
and nerves
(a)
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The Testes
• Interstitial (Leydig) cells outside the
seminiferous tubules produce androgens
Figure 27.3c
Spermatogenic
cells in tubule
epithelium
Interstitial cells
Areolar
connective
tissue
SpermMyoid
cells
(c)
Seminiferous
tubule
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The Penis
• Spongy urethra and three cylindrical bodies of erectile tissue (spongy network of connective tissue and smooth muscle with vascular spaces)
• Corpus spongiosum surrounds the urethra and expands to form the glans and bulb
• Corpora cavernosa are paired dorsal erectile bodies
• Erection: erectile tissue fills with blood, causing the penis to enlarge and become rigid
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The Male Duct System
• Epididymis
• Ductus deferens
• Ejaculatory duct
• Urethra
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Urethra
• Conveys both urine and semen (at different
times)
• Has three regions
1. Prostatic urethra
2. Membranous urethra
3. Spongy (penile) urethra
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Accessory Glands: Seminal Vesicles
• Produces viscous alkaline seminal fluid
• Fructose, ascorbic acid, coagulating enzyme
(vesiculase), and prostaglandins
• 70% of the volume of semen
• Duct of seminal vesicle joins the ductus
deferens to form the ejaculatory duct
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Accessory Glands: Prostate
• Encircles part of the urethra inferior to the
bladder
• Secretes milky, slightly acid fluid:
• Contains citrate, enzymes, and prostate-
specific antigen (PSA)
• Plays a role in the activation of sperm
• Enters the prostatic urethra during ejaculation
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Accessory Glands: Bulbourethral Glands
(Cowper’s Glands)
• Pea-sized glands inferior to the prostate
• Prior to ejaculation, produce thick, clear
mucus
• Lubricates the glans penis
• Neutralizes traces of acidic urine in the urethra
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Semen
• Mixture of sperm and accessory gland
secretions
• Contains nutrients (fructose), protects and
activates sperm, and facilitates their
movement (e.g., relaxin)
• Prostaglandins in semen
• Decrease the viscosity of mucus in the cervix
• Stimulate reverse peristalsis in the uterus
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Semen
• Alkalinity neutralizes the acid in the male
urethra and female vagina
• Antibiotic chemicals destroy certain bacteria
• Clotting factors coagulate semen just after
ejaculation, then fibrinolysin liquefies it
• Only 2–5 ml of semen are ejaculated,
containing 20–150 million sperm/ml
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Meiosis
• Gamete formation involves meiosis
• Nuclear division in the gonads in which the
number of chromosomes is halved (from 2n
to n)
• Two consecutive cell divisions (meiosis I
and II) following one round of DNA replication
• Produces four daughter cells
• Introduces genetic variation
Figure 27.7b
Basal lamina
Spermatogonium
(stem cell)
Mitosis
Growth
Late spermatids
Early
spermatids
Secondary
spermatocytes
Primary
spermatocyte
Spermatozoa
Type B daughter cell
Enters meiosis I
and moves to
adluminal
compartmentMeiosis I
completed
Meiosis II
Type A daughter cell
remains at basal lamina
as a stem cell
(b) Events of spermatogenesis,
showing the relative position
of various spermatogenic cells
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Spermiogenesis: Spermatids to Sperm
• Spermatids lose excess cytoplasm and form a
tail, becoming spermatozoa (sperm)
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Spermatogenic
cells in tubule
epithelium
Interstitial cells
Areolar
connective
tissue
SpermMyoid
cells
(c)
Seminiferous
tubule
Figure 27.7c
Basal lamina
Spermatogonium
(stem cell)
Cytoplasm of adjacent
sustentacular cells Sustentacular
cell nucleus
Tight junction between
sustentacular cells
Lumen of
seminifer-
ous tubule
Late spermatids
Early
spermatids
Secondary
spermatocytes
Cytoplasmic
bridge
Primary
spermatocyte
Spermatozoa
Type B daughter cell
Type A daughter cell
remains at basal lamina
as a stem cell
(c) A portion of the seminiferous tublule wall, showing the spermato-
genic cells surrounded by sustentacular cells (colored gold)
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Hormonal Regulation of Male Reproductive
Function
• A sequence of hormonal regulatory events
involving the hypothalamus, anterior pituitary
gland, and the testes
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Testosterone is the final trigger for
spermatogenesis
Feedback inhibition on the hypothalamus and
pituitary results from
• Rising levels of testosterone
• Inhibin (released when sperm count is high)
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Mechanism and Effects of Testosterone
Activity
• Testosterone
• Synthesized from cholesterol
• Transformed to exert its effects on some target
cells
• Dihydrotestosterone (DHT) in the prostate
• Estrogen in some neurons in the brain
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Mechanism and Effects of Testosterone
Activity
• Prompts spermatogenesis
• Targets all accessory organs; deficiency leads
to atrophy
• Has multiple anabolic effects throughout the
body
• Is the basis of the sex drive (libido) in males