THE REPRODUCTIVE SYSTEMS

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THE REPRODUCTIVE SYSTEMS

• Overview of reproduction
• Male reproductive system -- scrotum
• Testis
• Spermatogenesis
• Spermiogenesis
• Hormonal control of male reproduction
• The spermatic ducts
• Urethra
• Accessory sex glands
• Semen (seminal fluid)
• Penis
• Female reproductive organs
• Ovary
• Oögenesis
• Follicles and the ovarian cycle I
• Follicles and the ovarian cycle II
• Uterine tubes
• Uterus
• Vagina

• Female reproductive cycle
• Estrogen secretion and control
• Female cycle phases I
• Female cycle phases II
• Sexual responses

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OVERVIEW OF REPRODUCTION
What is the essential difference between mitosis
and meiosis?
What is the essence of reproduction?
biparental, and therefore not genetically
identical gametes fertilization produces a
zygote, which has its own genetics
Primary sex organs (gonads ovaries and
testes) Secondary sex organs everything else
related to reproduction
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MALE REPRODUCTIVE SYSTEM -- SCROTUM
Dartos fascia (muscle) Cremaster
muscle Temperature regulation Cremaster
reflex Descent of the testes
deep inguinal ring inguinal canal superficial
inguinal ring
internal abdominal oblique muscle
inguinal canal
Spermatic cord
superficial ring
ductus deferens testicular artery pampiniform
plexus autonomic nerves
ductus deferens
transverse section of penis
testicular artery
scrotal septum
pampiniform plexus
epididymis
cremaster muscle
tunica albuginea of testis
Dartos fascia
skin of scrotum
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TESTIS
Tunica vaginalis Tunica albuginea 250-300
lobules Seminiferous tubules Germinal epithelium
tunica albuginea covering testis
two cell types
tunica vaginalis
germ cells spermatogenesis sustentacular
(Sertoli) cells spermiogenesis
secrete inhibin
seminiferous tubule
septa
germinal epithelium
lobule
lumen
Interstitial cells (of Leydig)
secrete testosterone
basement membrane
seminiferous tubule
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SPERMATOGENESIS
Spermatogonium (2n2c)
basement membrane interstitial tissue
Leydig cells
mitosis meiosis
spermatogonia
1º spermatocyte (2n4c)
1º spermatocytes
first meiotic division
2º spermatocytes and spermatids
2 2º spermatocytes (1n2c)
spermatozoa
second meiotic division
lumen
4 spermatids (1n1c)
Sertoli cell
spermatogonium
begin spermiogenesis
1º spermatocyte
2º spermatocytes and spermatids
spermatozoa
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SPERMIOGENESIS
Sustentacular (Sertoli) cell
head
nourishment waste removal blood-testis barrier
acrosome
midpiece
nucleus
tail
Anatomical maturation
head (nucleus acrosome) midpiece
(mitochondria) tail (flagellum)
mitochondria
flagellum
300 million sperm/day
SEM of sperm in lumen of seminiferous tubule
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HORMONAL CONTROL OF MALE REPRODUCTION
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THE SPERMATIC DUCTS
Straight tubules ? Rete testis ? Efferent
ductules ? Ductus epididymis ?
1. seminiferous tubule
4. efferent ductules
5. ductus epididymis
2. straight tubule
3. rete testis
functional maturation storage (40 60
days) resorption if unused
6. ductus deferens
Ductus (vas) deferens ?
path in the body terminate as ampulla joins
seminal vesicle duct
prostate gland
seminal vesicle
Ejaculatory duct
6. ductus deferens
passes into prostate gland joins urethra
8. urethra
7. ejaculatory duct
5. ductus epididymis
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URETHRA
Three parts
ampulla of ductus deferens
urinary bladder
prostatic membranous spongy (penile)
seminal vesicle
prostate gland
ejaculatory duct
ductus deferens
urethra
corpus spongiosum of penis
ductus epididymis
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ACCESSORY SEX GLANDS
Seminal vesicles (60 of semen)
prostate gland
fructose/other carbohydrates prostaglandins prosem
inogelin (fibrin-like)
Prostate gland (30 of semen)
citrate, calcium, phosphate ions clotting
enzymes serine protease
seminal vesicle
Bulbourethral glands
bulbourethral glands
pre-ejaculatory fluid mucus acid buffers
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SEMEN (SEMINAL FLUID)
Sperm (10) accessory gland secretions (90) 2
5 ml per ejaculate with 50 120 million sperm
per ml What happens at ejaculation?
prostatic fluid and seminal vesicle fluids mixed
at emission proseminogelin ? seminogelin by
prostatic clotting enzymes
semen becomes sticky entangles sperm, sticks
semen to vaginal and cervical surfaces prevents
semen from draining out of vagina
prostatic serine protease breaks down seminogelin
after 20-30 min
semen liquifies sperm become very
active prostaglandins help to thin cervical mucus
plug and may stimulate uterine
contractions, helping sperm into uterine cavity
2 requirements for sperm motility are met
vaginal pH (3.5 4.0) brought to 7.5 fructose
and other sugars provide substrate for sperm ATP
production
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PENIS
Parts
prostatic urethra
prostate gland
membranous urethra
internal root and crura external
bulbourethral gland
pelvic diaphragm
bulb of the penis
body (shaft) glans (head) with prepuce
crus of the penis
penile urethra
corpora cavernosa
corona
Erectile tissues
deep artery of the penis
corpora cavernosa (2) corpus spongiosum
corpus spongiosum
glans penis
Erectile physiology
skin
superficial dorsal vein
dorsal artery
dilation of deep artery lacunae fill with
blood erectile tissues expand and
harden penile veins pinched off
connective tissue
deep dorsal vein
corpus cavernosum
deep artery
tunica albuginea
corpus spongiosum
urethra
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FEMALE REPRODUCTIVE ORGANS
Internal genitalia
uterus
urinary bladder
2 ovaries 2 oviducts (uterine or Fallopian
tubes) uterus vagina
rectum
pubic symphysis
clitoris
External genitalia
anus
urethra
vagina
clitoris labia minora labia majora
ANTERIOR
urinary bladder
oviduct
uterus
Breasts and mammary glands
ovary
rectum
cecum
ileum
view from above into pelvis
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OVARY
Development Location Structure
tunica albuginea
follicles
medulla
tunica albuginea cortex with follicles medulla
with blood supply ligaments
cortex
ovary
oviduct
ovary
mesovarium mesosalpinx ovarian ligament broad
ligament suspensory ligament
broad ligament
mesosalpinx
uterus
ovarian ligament
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OOGENESIS
Mitosis in fetal life 2 meiotic arrests Total
number of ova
7 million at 5th month 2 million at birth 40,000
at puberty Use 40 50 per cycle (others
just die off) 480 ovulations 13 per year for
37 years
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FOLLICLES AND THE OVARIAN CYCLE I
Primordial follicle
primary oöcyte arrested in prophase I 1 layer
of flattened follicle cells
Corpus luteum remnants of follicle cells after
ovulation Corpus albicans scarred over corpus
luteum
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FOLLICLES AND THE OVARIAN CYCLE II
primary unilaminar follicle
primary multilaminar follicle
secondary follicle
primordial follicles
secondary oöcyte surrounded by corona radiata
tertiary follicle
antrum
ovulated secondary oöcyte surrounded by corona
radiata
corpus albicans
follicle cells left behind in ovary
corpus luteum
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UTERINE TUBES
Also known as
oviduct
ampulla
infundibulum
oviducts Fallopian tubes
uterus
isthmus
Location Sections
fimbriae infundibulum ampulla isthmus
fimbriae
ovary
Histology
ciliated simple columnar muscularis
vagina
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UTERUS
Gross anatomy
uterus (anteverted position)
sections
vesicouterine pouch
rectum
fundus corpus (body) cervix
rectouterine pouch
landmarks
urinary bladder
uterine cavity
fundus
rectouterine pouch vesicouterine pouch
corpus
blood supply
radial artery
perimetrium
uterine arteries spiral arterioles
cervix
myometrium
Histology
endometrium
perimetrium myometrium endometrium
uterine gland
spiral arteriole
stratum basalis stratum functionalis
uterine artery
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VAGINA
Location Gross anatomy
uterus
urinary bladder
posterior fornix
fornix (anterior and posterior) rugae hymen introi
tus (orifice)
anterior fornix
introitus
Histology
stratified squamous no vaginal glands
uterus
cervical mucous glands transudation of tissue
fluid cells secrete glycogen
urinary bladder
pubic symphysis
vagina
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EXTERNAL GENITALIA AND THE PERINEUM
Vulva (pudendum)
mons pubis
mons pubis labia majora labia minora vestibule
labium majus
prepuce
clitoris
labium minus
urethral orifice
vaginal introitus
vestibule
urethral orifice vaginal introitus
anus
clitoris with prepuce
glans
pubic symphysis
clitoris
glans crus
crus
vestibular bulbs vestibular glands paraurethral
glands
paraurethral gland
vestibular bulb
ischial tuberosity
Perineum
vestibular gland
urogenital triangle anal triangle
anus
coccyx
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THE BREASTS AND MAMMARY GLANDS
Location 15 20 lobes Ducts
pectoralis major
mammary glands
alveolar ducts ? lactiferous sinus ? lactiferous
duct
rib
nipple
adipose tissue
areola
pectoralis major
lactiferous sinus
Nipple and areola Development Lactation
alveolar ducts
lactiferous duct
lactiferous sinus
alveolar ducts
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FEMALE REPRODUCTIVE CYCLE
Ovarian cycle Uterine (menstrual) cycle Hormonal
regulation
hypothalamic Gn-RF
anterior pituitary gland
FSH
LH
Gn-RF FSH LH estrogen progesterone inhibin relaxin
ovaries
follicle development
ovulation ? corpus luteum
estrogen
relaxin inhibin progesterone estrogen
relaxin -- relaxes pubic symphysis/cervical
dilation
inhibin -- inhibits Gn-RF and FSH
progesterone -- stimulates secretory
endometrium prepares
mammary glands for milk synthesis
estrogen -- primary sex characteristics (before
birth) secondary sex
characteristics (at puberty) enlargement of
sex organs female sexual
behavior (with testosterone)
endometrial proliferation
increased proteins anabolism
aids in fluid and electrolyte balance
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ESTROGEN SECRETION AND CONTROL
Estrogen is secreted by follicular cells prior to
ovulation and by the corpus luteum after
ovulation.
Low levels of estrogen allow Gn-RF secretion and
the anterior pituitary gland to secrete
FSH, which initiates follicular development
at the beginning of a new cycle.
High levels of estrogen allow Gn-RF secretion and
the anterior pituitary gland to secrete LH,
which stimulates ovulation, thus leading to
formation of the corpus luteum.
Moderate levels of estrogen inhibit Gn-RF
secretion and therefore inhibits FSH and LH.
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FEMALE CYCLE PHASES I
Average cycle 28 days
Phases Changes
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FEMALE CYCLE PHASES II
hypothalamic Gn-RF
anterior pituitary gland
LH
FSH
follicles
estrogen
progesterone
stratum functionalis

• 14
  26 28
• days of menstrual cycle

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SEXUAL RESPONSES
MALE
FEMALE
excitement
excitement and plateau
erection bulbourethral gland lubrication
vaginal transudate lubrication from vestibular
glands orgasmic platform formed tenting effect
orgasm
orgasm
emission ejaculation
resolution
resolution
detumescence refractory period
detumescence
parasympathetic control in blue sympathetic
control in red
end