1. Reproductive Systems
Male Reproductive System Female Reproductive System
• Testes • Ovaries
• Epididymides • Uterine Tubes
• Ductus Deferentia • Uterus
• Seminal Vesicles • Vagina
• Labia Majora
• Prostate Gland
• Labia Minora
• Bulbourethral Glands
• Clitoris
• Scrotum • Vestibule
• Penis • Mammary Glands

2. Male Reproductive System

3. Male Reproductive Organs
• Testes
– Primary sex organs
– Sperm cells & male sex hormones formed here
– 2 testes w/in cavity of scrotum
– Tough, white, fibrous capsule encloses each testis
– Connective tissue thickens & extends into testis forming 250 lobules
– Each lobule contains 1-4 seminiferous tubules
– Tubules unite to form complex network of channels that give rise to ducts
that join tube called epididymis
– Specialized stratified epithelium called spermatogenic cells line the
seminiferous tubules & give rise to sperm cells
– Interstitial cells lie in space between seminiferous tubules &
produce/secrete male sex hormones

4. Fig. 19.02a
Structure
of the
testis

5. Sperm Cell Anatomy
• Tiny tad-pole shaped cell
• 0.06 millimeters long
• Oval Head
– Nucleus w/ compacted chromatin
consisting of 23 chromosomes
– Acrosome contains enzymes to
help penetrate egg cell
• Midpiece
– Many mitochondria organized in
a spiral
• Tail
– Flagellum
– Allows for movement to propel
sperm through fluid

6. Spermatogenesis
• Occurs continually starting at puberty
• During embryonic development, hormones stimulate
spermatogonia (undifferentiated spermatogenic cells) to
undergo mitosis
• Each cell division gives rise to 2 new cells
– Type A maintains supply of undifferentiated cells
– Type B differentiates becoming a primary spermatocyte
• Spermatocytes reproduce by cell division called meiosis
• Meiosis contains 2 successive divisions: 1st & 2nd meiotic
divisions

7. Spermatogenesis
• Before Meiosis I, each homologous chromosome is replicated
• Meiosis I separates homologous chromosome pairs
• Haploid: each cell undergoing meiotic division begins w/ 1 member
of each homologous pair
– Haploid cell has 1 set of chromosomes

8. Spermatogenesis
• Meiosis II separates
chromatids, producing cells whose
chromosomes are no longer in
replicated form
• After meiosis II, each chromatid is
independent chromosome
• For each primary spermatocyte
undergoing meiosis, 4 sperm cells w/
23 chromosomes result
• Each primary spermatocyte divides to
form 2 secondary spermatocytes;
each of these divide to form 2
spermatids (mature into sperm cells)

9. Male Internal Reproductive Organs
• Specialized to nurture & transport sperm
• Epididymides (2)
– Tightly coiled, threadlike tubes 6 meters long
– Each connected to ducts w/in a testis
– Emerges from top of testis, descends along posterior surface, & comes upward to
become ductus deferens
• Ductus Deferentia (2)
– Muscular tubes 45 cm long
– Pass upward in lower abdominal wall, enter pelvic cavity, & end behind urinary
bladder
– Unite w/ duct of seminal vesicle to form ejaculatory duct, which passes through
prostate gland & empties into urethra
• Seminal Vesicles (2)
– Convoluted, saclike structures 5 cm long
– Attach to ductus deferens near base of urinary bladder
– Lining secretes alkaline fluid to regulate pH of tubular contents
– Secretes fructose – provide energy to sperm
– Secretes prostaglandins – stimulate muscular contractions w/in female
reproductive organs

10. Male Internal Reproductive Organs
• Specialized to nurture & transport sperm
• Prostate Gland
– Chestnut shaped structure that surrounds part of urethra, inferior to bladder
– Secretes thin, milky fluid w/ alkaline pH
– Secretion neutralizes fluid containing sperm cells
– Enhances motility of sperm cells & helps neutralize acidic secretions of vagina
• Bulbourethral Glands (2)
– Inferior to prostate gland
– Secrete mucus-like fluid in response to sexual stimulation
– Fluid lubricates end of penis in preparation for sexual intercourse
• Semen
– Fluid secreted by male urethra during ejaculation
– Consists of sperm & secretions of seminal vesicles, prostate gland, &
bulbourethral glands
– Slightly alkaline & includes prostaglandins & nutrients

11. Male External Reproductive Organs
• Scrotum
– Pouch of skin & subcutaneous tissue hanging from lower abdominal
region posterior to penis
– Contains 2 chambers each of which hold a testis
– Chambers contain serous membrane to cover testis & allow for
smooth movement
– Protects & helps regulate temperature of testes
• Penis
– Cylindrical organ that conveys urine & semen through urethra
– Shaft of penis has 3 columns of erectile tissue
– Urethra extends through glans penis which is cone shaped sensitive
end of penis

12. Hypothalamic & Pituitary Hormones
• Hypothalamus secretes gonadotropin-releasing hormone (GnRH)
• Stimulates anterior pituitary gland to release
gonadotropins, luteinizing hormone, & follicle-stimulating
hormone
• Luteinizing Hormone
– Promotes development of interstitial cells of testes
– In turn, testes secrete male sex hormones
• Follicle-Stimulating Hormone
– Stimulates seminiferous tubules to respond to effects of testosterone
– FSH & testosterone stimulate spermatogenic cells to undergo
spermatogenesis
– Seminiferous cells also secrete hormone inhibin, which inhibits anterior
pituitary gland by negative feedback

13. Male Sex Hormones = Androgens
• Testosterone
– Most important androgen
• Actions:
– Increased growth of body hair
– Enlargement of larynx & thickening of vocal folds
– Thickening of skin
– Increased muscular growth, broadening of shoulders, & narrowing of
waist
– Thickening & strengthening of bones
– Increases rate of cellular metabolism & RBC production
– Stimulates sexual activity by affecting certain parts of brain

14. Regulation of Testosterone
• Hypothalamus regulates
through negative feedback
• Increasing Concentration
– Inhibits hypothalamus
– stimulation of anterior
pituitary gland decreases
– As secretion of LH
falls, testosterone release
from cells decreases
• Decreasing Concentration
– Hypothalamus stimulates
anterior pituitary gland to
release LH
– Secretion causes interstitial
cells to release testosterone

15. Female Reproductive System

16. Female Reproductive Organs
• Ovaries (2)
– Solid, ovoid structures
– Lie in shallow depressions in lateral wall of pelvic cavity
– Divided into 2 regions – inner medulla & outer cortex
– Ovarian medulla composed of loose connective tissue w/ many blood
vessels, lymphatic vessels, & nerve fibers
– Ovarian cortex consist of compact tissue & granular appearance due to tiny
masses of cells called ovarian follicles
– Layer of cuboidal epithelium covers ovary’s free surface
– Beneath layer of epithelium is layer of dense connective tissue

17. Primordial Follicles
• During prenatal development, small group of cells of ovarian
cortex form several millions primordial follicles
• Each follicle = single, large cell called primary oocyte
• Each primary oocyte surrounded by epithelial cells called
follicular cells
• Once primordial follicles appear, no new ones form
• Number of ooyctes in ovary steadily decline over time

18. Oogenesis
• Beginning at puberty, some primary oocytes stimulated to continue
meiosis
• When primary oocyte divides, cytoplasm distributed unequally
• One of resulting cells, secondary oocyte, is large
• Other resulting cell, first polar body, is small
• Secondary oocyte represents future egg cell
– If fertilized by sperm, divides unequally to produce a 2nd polar body & a
large fertilized egg cell called a zygote
• Polar bodies degenerate

19. Oogenesis

20. Follicle Maturation
• w/ each reproductive cycle, some primordial follicles mature into primary
follicles
• During maturation, primary oocyte enlarges & surrounding follicular cells
proliferate by mitosis
• Follicular cells organize into layers & a cavity appears in the cellular mass
• Clear follicular fluid fills cavity & bathes primary oocyte
• Enlarging fluid filled cavity presses primary oocyte to one side
• Mature follicle buldges outward on ovary surface
• Secondary oocyte w/in mature follicle is large, spherical cell, surrounded by
glycoprotein called zona pellucida & attached to mantle of follicular cells

21. Follicle Maturation

22. Ovulation
• As follicle matures, primary oocyte undergoes oogenesis giving rise to
secondary oocyte & 1st polar body
• Ovulation: releases secondary oocyte & 1st polar body w/ 1 or 2
surrounding layers of follicular cells from mature follicle
• Release of LH triggers ovulation
• Eventually mature follicle’s wall ruptures & follicular fluid & secondary
oocyte ooze from ovary surface
• After ovulation, secondary oocyte & surrounding follicular cells propelled
to uterine tube
• If not fertilized, oocyte degenerates

23. Female Internal Reproductive Organs
• Uterine Tubes aka Fallopian Tubes (2)
– 10 cm long passing medially to uterus, penetrates its wall & opens into uterine
cavity
– Near each ovary, expands to form infundibulum, which partially encircles ovary
– Simple columnar epithelial cells line uterine tubes
– Epithelium secrete mucus which cilia move towards uterus
– Ciliary action & peristaltic contractions help transport secondary oocyte down
uterine tube
– Fertilization occurs in uterine tube
• Uterus
– Receives embryo that develops from fertilized egg in uterine tube
– Hollow, muscular organ located medially in anterior part of pelvic
cavity, superior to vagina
– Uterine tubes enter at top of uterus
– Lower third of uterus, cervix, extends downward into upper part of vagina
– Cervix surrounds opening through which uterus opens to vagina

24. Female Internal Reproductive Organs
• Uterus (Cont.)
– Thick wall w/ 3 layers
– Endometrium (inner mucosal layer) – covered w/ columnar epithelium &
contains tubular glands
– Myometrium (thick, middle layer) – consist of bundles of smooth muscle fibers
– Perimetrium (outer serosal layer) – covers body of uterus & part of cervix
• Vagina
– fibromuscular tube extending from uterus to outside of body
– Conveys uterine secretions, receives penis during sexual intercourse, &
provides open channel for birth
– Wall has 3 layers
• Inner mucosal layer of stratified squamous epithelium
• Middle muscular layer consisting of smooth muscle
• Outer fibrous layer consists of dense connective tissue interlaced w/ elastic fibers

25. Female External Reproductive Organs
• Labia Majora
– Rounded folds of adipose tissue & thin layer of smooth muscle, covered by
skin
– Enclose & protect other external reproductive organs
• Labia Minora
– Flattened, longitudinal folds between labia majora
– Composed of connective tissue richly supplied w/ blood vessels
• Clitoris
– Small projection at anterior end of vulva between labia minora
– Richly supplied w/ sensory nerve fibers
• Vestibule
– Enclosed space by labia minora
– Vagina opens into posterior portion of vestibule & urethra open in the
midline
– Pair of vestibular glands lie on either side of vaginal opening

26. Female External Reproductive Organs

27. Female Sex Hormones
• Hypothalamus, anterior pituitary gland, & ovaries secrete
hormones
• Hypothalamus secretes gonadotropin-releasing hormone
• Anterior pituitary secretes FSH & LH which play role in
controlling female sex cell maturation & in producing female
sex hormones
• Female Sex Hormones = Estrogen & Progesterone

28. Female Sex Hormones
• Estrogen
– Ovaries are primary source
– Development of breasts & ductile system of mammary glands in
breasts
– Increased deposition of adipose tissue in subcutaneous
layer, breasts, thighs, & buttocks
– Increased vascularization of skin
• Progesterone
– Ovaries are primary source
– Promotes changes in uterus during female reproductive cycle
– Affects mammary glands
– Helps regulate secretion of gonadotropins from anterior pituitary
gland

29. Female Reproductive Cycle

31. Mammary Glands
• Accessory organs specialized to secrete milk following
pregnancy
• Located in subcutaneous tissue of anterior thorax w/in
elevations called breasts
• Mammary gland composed of 15-20 lobes

32. Mammary Glands
• Each lobe contains alveolar glands & an alveolar duct which
leads to lactiferous duct
• Dense connective tissue & adipose tissue separate lobes
• Tissues support glands & attach them to fascia of underlying
pectoral muscles
• Other connective tissue which forms dense suspensory
ligaments, extends inward from dermis to fascia, helping
support breast
• Ovarian hormones stimulate development of glands in
females