Chapter 23
The Reproductive
Systems
Copyright 2010, John Wiley & Sons, Inc.
Male Reproductive System
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Organs: testes, ducts, glands & supporting
structures
Ducts: epdidymis, ductus deferens,
ejaculatory ducts & urethra
Glands: seminal vesicles, prostate,
bulbourethral glands
Supporting structures include scrotum &
penis
Copyright 2010, John Wiley & Sons, Inc.
Male Reproductive System
Copyright 2010, John Wiley & Sons, Inc.
Scrotum
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Pouch that supports the testes
Septum separates into separate sections for
each testis
Sperm requires temperatures 2-3°C below
body temperature
Allows raising and lowering testes to adjust
temperature
Copyright 2010, John Wiley & Sons, Inc.
Testes
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Paired oval glands
Develop on embryo’s posterior wall and
descend into scrotum
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Starts in 7th month
200-300 lobules containing seminiferous
tubules
Lined with spermatogenic cells: spermatagonia
& sertoli cells
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Testes
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Testes
Copyright 2010, John Wiley & Sons, Inc.
Spermatogenesis
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Stages: meiosis I, meiosis II, spermiogenesis
Occurs in seminiferous tubules
Cell types involved: spermatagonia, sertoli
cells & interstitial cells (leydig cells)
Move through rete testes
 epididymis
Copyright 2010, John Wiley & Sons, Inc.
Meiosis
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Cells have 23 pairs of chromosomes
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Gametes are Haploid
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Diploid = paired homologous chromosomes
Unpaired chromosomes
Meiosis is the process by which this can
happen
Required for gamete production
Copyright 2010, John Wiley & Sons, Inc.
Spermatogenesis Stages
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Takes ~65–75 days from first division to
release
Spermatogonium divides: mitosis
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One cell is stem cell other differentiates into
primary (1o) spermatocyte
Meiosis I: chromosomes replicate
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Line up as pairs of homologous chromosomes
Chromosomes twist and some exchange of
material between chromosomes can occur
Each homologous pair separates and a member
moves to opposite end of cell 
After cell division each cell is haploid
Copyright 2010, John Wiley & Sons, Inc.
Spermatogenesis Stages
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The cells from meiosis I are: secondary
spermatocytes
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Meiosis II: divide again
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Each cell is haploid- has two copies of each
chromatid
One copy of each chromatid in each new cell
Cells are: spermatids
Copyright 2010, John Wiley & Sons, Inc.
Spermatogenesis Stages
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Spermiogenesis- each spermatid develops
into a sperm cell
Process requires support of Sertoli cell
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Often called “nurse cell”
Copyright 2010, John Wiley & Sons, Inc.
Spermatogenesis
Copyright 2010, John Wiley & Sons, Inc.
Spermatozoa Structure
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~300 million /day
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Life time ~ 48 hrs in female tract
Structure: Head, middle, tail
Tail- flagellum = motility
Middle: mitochondria = energy
Head-chromosomes + acrosomal cap
Acrosome-enzymes-  penetrating egg
Copyright 2010, John Wiley & Sons, Inc.
Spermatozoa
Structure
Copyright 2010, John Wiley & Sons, Inc.
Hormonal Control
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At puberty- hypothalamus  GnRH 
Pituitary LH & FSH
LH Leydig cells  testosterone 
Negative feedback to suppress LH & GnRH
FSH + testosterone stimulate
spermatogenesis
Sertoli cells  inhibin  inhibits FSH release
 optimum sperm production
Copyright 2010, John Wiley & Sons, Inc.
Hormonal
Control
Copyright 2010, John Wiley & Sons, Inc.
Androgen Effects
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Prenatal: male pattern of development:
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Puberty: enlargement of organs, secondary
characteristics
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Male ducts, descent of testes, external genitals
and brain regions
Muscular and skeletal growth, hair patterns,
thickening of skin
Sexual function: sexual behavior,
spermatogenesis and libido
Stimulation of anabolism: stimulate protein
synthesis and muscle and bone growth
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Ducts: Sperm Route
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Epdidymis vas (ductus) deferens
 ejaculatory duct (by seminal vesicles)
 urethra in prostate
Pass bulbourethral glands (alkaline + mucus
fluid)
 penis and ejaculation
Copyright 2010, John Wiley & Sons, Inc.
Accessory Glands
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Seminal vesicles: seminal fluid
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Prostate: surrounds upper urethra
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Fructose (sperm ATP production
+ alkalinity (neutralize acid in tracts)
+ prostaglandins-activation of sperm
Increases volume + adds antibiotics
Bulbourethral glands
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More alkalinity + mucus fluid
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Penis
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Contains urethra- root, body & glans penis
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Root: attached portion
Body: 3 cylindrical masses erectile
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Passage for semen and urine
Dorsal: Corpora Cavernosa Penis
Midventral: Corpus Spongiosum penis- contains
urethra
Glans penis has external urethral oriface
Uncircumcised glans covered by prepuce
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Arousal & Ejaculation
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Parasympathetic impulses erection
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Dilation of penile arteries
Volume compresses veins so outflow is slowed
Ejaculation is a Sympathetic reflex
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Peristaltic contractions in ductus deferens,
seminal vesicles, ejaculatory ducts & prostate
emission
Sphincter at urinary bladder closes
Forceful release of semen from urethra
Copyright 2010, John Wiley & Sons, Inc.
Female Reproductive System
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Ovaries: paired organs- produce
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Secondary oocytes ova (after fertilization)
Hormones: progesterone & estrogens
From same embryonic tissue as testes
Uterine (fallopian) tubes & uterus
Vagina
External organs (vulva or pudendum)
Copyright 2010, John Wiley & Sons, Inc.
Female Reproductive System
Copyright 2010, John Wiley & Sons, Inc.
Histological Structure
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Germinal epithelium: covers surface
Ovarian cortex: connective tissue containing
follicles
Follicle; oocyte + surrounding cells
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Surrounding cells nourish oocyte & produce
hormones
Grows during maturation 
Graafian follicle ovulation
Post ovulation  corpus luteum
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Progesterone, relaxin & inhibin
Copyright 2010, John Wiley & Sons, Inc.
Histological Structure
Copyright 2010, John Wiley & Sons, Inc.
Oogenesis
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Begins before birth
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Meiosis I- start before birth & finish at puberty
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Oocytes not continually produced
During fetal development form oogonia
Before birth some  primary oocytes
Monthly hormones  some to complete meiosis I
Two uneven haploid cells = secondary
oocyte & polar body (discarded)
Copyright 2010, John Wiley & Sons, Inc.
Oogenesis
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Secondary oocyte has most of cytosol
Then begins meiosis 2 & stops
Then ovulation into uterine tube
If fertilization then meiosis II is completed
ovum + 2nd polar body
Nuclei of sperm & ovum unite
Diploid zygote
Copyright 2010, John Wiley & Sons, Inc.
Oogenesis
Copyright 2010, John Wiley & Sons, Inc.
Uterine Tubes
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Two tubes- extend laterally from uterus
End in fringe  fimbriae
Fimbriae sweep secondary oocyte into tube
Oocyte moved by cilia lining wall
Zygote reaches uterus in ~7 days
Copyright 2010, John Wiley & Sons, Inc.
Uterus
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Pathway for sperm & site of implantation
Fundus: dome-shaped area above tubes=
Body: tapering central portion
Cervix: narrow opening into vagina
Uterine cavity: interior of body
Copyright 2010, John Wiley & Sons, Inc.
Vagina
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Extends from exterior to cervix
Receptacles for penis and outlet for
menstrual flow
Fornix- recess surrounds cervix
Acid environment- prevents bacterial growth
Smooth muscular layer- adjusts for
intercourse or birth
Thin membrane fold can cover vaginal orifice
= hymen
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Uterus and Vagina
Copyright 2010, John Wiley & Sons, Inc.
Perineum and Vulva
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Perineum: Diamond-shaped area between
thigh & buttocks of both males & females
Vulva or pudendum = external genitalia
Mons pubis- elevation of adipose tissue
Labia majora- extends back from mons pubis
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Same fetal tissue as scrotum
Labia minora- internal to majora
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Perineum and Vulva
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Clitoris: small cylindrical mass of erectile
tissue & nerves
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Vestibule: between labia minora
External urethral oriface: anterior to vaginal
oriface
Paraurethral glands: either side of urethra
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Also contains prepuce & glans
Same embryonic tissue as prostate
Secretes mucus
Greater vestibular glands- adds to mucus
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Comparable to bulbourethral glands
Copyright 2010, John Wiley & Sons, Inc.
Perineum and Vulva
Copyright 2010, John Wiley & Sons, Inc.
Mammary Glands
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Modified suduriferous glands
Nipple: pigmented projection with
openings
Areola: surrounds nipple
Internally:15-20 lobes lobules alveoli =
milk secreting glands
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Matures at puberty
Lactation = synthesis, secretion & ejection
of milk
Copyright 2010, John Wiley & Sons, Inc.
Mammary Glands
Copyright 2010, John Wiley & Sons, Inc.
Female Reproductive Cycle
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24-34 days- cycles in both ovaries & uterus
Ovarian cycle = maturation of follicle,
ovulation & corpus luteum formation
Uterine Cycle = menstrual cycle
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Controlled by hormones from ovary
Estrogens  growth of endometrium
Progesterone supports endometrium for
implantation
Combine cycles = reproductive cycle
Copyright 2010, John Wiley & Sons, Inc.
Female Reproductive Cycle
Copyright 2010, John Wiley & Sons, Inc.
Female Reproductive Cycle
Copyright 2010, John Wiley & Sons, Inc.
Hormonal Regulation
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GnRH (hypothalamus) controls
GnRH FSH & LH
FSH follicle growth & estrogen secretion
High estrogen  LH surge  ovulation
LH supports corpus luteum  progesterone
& estrogen secretion + relaxin & inhibin
Inhibin  decreased FSH release
Copyright 2010, John Wiley & Sons, Inc.
Hormones
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Estrogen development & maintenance of
reproductive structures & secondary
characteristics
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 protein synthesis & growth
Lower blood cholesterol level
Progesterone maintains myometrium for
implantation
Relaxin: relaxes uterus- inhibits myometrium
Inhibin: inhibits FSH release
Copyright 2010, John Wiley & Sons, Inc.
Phases of Cycle
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Menstrual phase: ~1st 5 days of cycle
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Several Ovarian follicles enlarge
Decreased progesterone & estrogen uterine
arteries constrict endometrium sloughs off
Preovulatory: between menstruation &
ovulation
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Ovaries: follicles grow & secrete estrogen &
inhibin one dominates
Uterus: growth of new endometrium
Copyright 2010, John Wiley & Sons, Inc.
Phases of Cycle
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Ovulation
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Release of 2o oocyte with LH surge
Postovulatory
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Ovaries: follicle collapses corpus luteum (luteal
phase)
If no fertilization  FSH & LH  corpus albicans
& decreased Progesterone  menstruation
Copyright 2010, John Wiley & Sons, Inc.
Phases of Cycle
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If fertilization & division human chorionic
gonadotrophin (hCG) stimulates corpus
luteum secretion
Uterus: Progesterone & estrogens
complete development of uterus for
implantation
Copyright 2010, John Wiley & Sons, Inc.
Summary of Hormonal Interactions
Copyright 2010, John Wiley & Sons, Inc.
Birth Control Methods
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Surgical: vasectomy in males
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Tubal ligation in females
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IUD, condoms, cervical cap
Timing
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Oral hormones, implants, injections, spermicide
Blocking physically
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Close uterine tubes
Chemical interference
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Ductus deferens segment removed
Temperature, mucus charting, calendar
Abortion
Copyright 2010, John Wiley & Sons, Inc.
Aging
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Puberty- pulses of LH & FSH
Rise in sex steroids
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Follicles become exhausted menopause
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Growth & secondary characteristics
Start of female reproductive cycle
Estrogen secretion declines
Lose feedback on pituitary  high FSH & LH
Decline in estrogen supported functions
In males: slower decline of function
Copyright 2010, John Wiley & Sons, Inc.
End of Chapter 23
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Copyright 2010 John Wiley & Sons, Inc.
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Copyright 2010, John Wiley & Sons, Inc.