The female reproductive system consists of internal and external organs. The internal organs include the ovaries, which produce eggs and hormones, the fallopian tubes which pick up eggs from the ovaries, and the uterus which nourishes a developing embryo. The external organs include the vagina and vulva. The female reproductive system undergoes monthly changes in a menstrual cycle regulated by hormones, with the goal of reproduction through ovulation, fertilization, and embryo implantation.

1. The Reproductive
System

2. Similarities and differences between males
and females, but same goal: new life
 Primary sex organs: gonads
 Testes in males
 Ovaries in females
 These produce the gametes (sex cells)
 Sperm in males
 Ovum (egg) in females
 Endocrine function also: secretion of hormones
 Accessory sex organs
 Internal glands and ducts
 External genitalia
2

3. Male reproductive system
 Testes (singular testis) or testicles: the gonads
 In embryo, first develop in posterior abdominal wall, then migrate
 Internal body temp too hot for viable sperm
 Temp cooler in the scrotum because of superficial position
3

4.  Scrotum (=pouch) has septum dividing it
 Each testis is about 2.5cm x 4 cm in size, within scrotum
 Dartos and cremaster muscles move testes in response to hot or cold
 Serous sac partially encloses each testis: the tunica vaginalis*
 Develops as outpocketing of peritoneal cavity
 Just deep to tunica vaginalis is tunica albuginea* - fibrous capsule
 Septal extensions of it divide testis into 250-300 lobules
 Each lobule contains 1-4 coiled seminiferous tubules: make sperm
*
*
4

5.  Just deep to tunica vaginalis is tunica albuginea* - fibrous capsule
 Septal extensions of it divide testis into 250-300 lobules*
 Each lobule contains 1-4 coiled seminiferous tubules*: make sperm
 Converge to form straight tube (tubulus rectus), then conveys sperm into rete testis
 Sperm leave testis through efferent ductules which enter epididymis*
 Blood supply: pampiniform plexus: from L2 not pelvic level, since descended
from abdomen
Pampiniform
plexus
epididymis
* *
*
* *
*
*
(lateral views)
* Epididymis is
comma-shaped
5

6. Spermatogenesis: Cross section of seminiferous
tubule
sperm formation
 Begins at puberty
 400 million sperm/day
For baby not to end up with
twice as many chromosomes
as the parents, the sperm (as
well as the egg) needs to
have only half (1n) the # of
chromosomes (1 of each of
the 23)
(2n means 2 of each
chromosome, one from each
parent, totaling 23 pairs = 46
chromosomes)
 Three stages:
 Formation of spermatocytes
 Meiosis
 Spermiogenesis
6

7.  1st stage: formation of Cross section of seminiferous
spermatocytes tubule
 Spermatogonia are stem
cells
 Least differentiated
(earliest in the process)
 Lie in basal lamina
 Divide continuously by
mitosis (result 2n or diploid):
daughter cells A (remains a
stem cell) or B (goes on)
 When start to undergo
meiosis are by definition
called spermatocytes
 2nd stage: meiosis I
 Each primary spermatocytes
(2n) undergoes meiosis I to
become 2 secondary
spermatocytes:
 Each secondary
spermatocyte undergoes
meiosis II to become 2
spermatids
 Therefore 4 total spermatids
from each spermatogonium
 3rd stage: spermiogenesis
 Spermatids differentiate into
sperm 7

8. Stage 3: Spermiogenesis: spermatid streamlined to sperm
 Head contains
 Nucleus with chromatid (genetic material)
 Acrosome with enzymes for penetrating egg
 Midpiece: mitochondria spiraled around the core of the tail
 Tail is an elaborate flagellum (allows sperm to swim) know
these
parts
8

9.  Sperm can swim only after they have left the *
testis
 Process of spermatogenesis is controlled by
two hormones
 FSH (follicle stimulating hormones) from anterior
pituitary
 Testosterone
 primary male hormone
 produces by testes
 Sperm surrounded by Sertoli* (sustenacular)
cells: tight junctions
 Prevents escape of unique antigens seen as foreign
 These would activate the immune system
 Autoimmune response would cause sterility
 Other functions as well
 Interstitial or Leydig cells: secrete androgens
 Male sex hormones
 Main one is testosterone
 Into blood, sustain all male sex characteristic and
sex organs
9

10.  Sperm leave testis though efferent ductules
 Lined by simple columnar epithelium
 Cilia and smooth muscle in wall help move sperm along
 Sperm mature in epididymus (20 days)
 Head of epididymus contains the efferent ductules which empty
into duct of the epididymus
 Sperm gain ability to swim
 Sperm can be stored in epididymus for several months
(reabsorbs fluid) Duct of epididymis: highly
coiled 6m long duct (pic left
is multiple coils of same
duct)
*Note pseudostratified
* columnar epithelium
Ductus (vas)
deferens:
note thick layers of
smooth muscle
10

11.  Sperm are ejaculated from the epididymus
 Not directly from the testes
 Vas deferens* (or ductus deferens) 45cm (18”)
 Stores and transports sperm during ejaculation
 Runs superiorly from scrotum within spermatic cord, through
inguinal canal and enters pelvis
 Histo: see previous slide •Vas* arches
medially over ureter
•Descends along
posterior wall of
bladder
•Ends in ampulla
which joins duct of
* seminal vesicle to
form short
ejaculatory duct
•Each ejaculatory
duct runs within
prostate where
empties into
prostatic urethra
11

12. Inguinal hernia
Spermatic cord:
• Vas deference is the largest
component
• Is a tube of fascia also
containing nerves and
vessels
• Runs in inguinal canal
Inguinal canal has 2 rings:
1. Superficial (medial)
2. Deep
12

13. Posterior view
Lateral view
 Seminal vesicles
 On posterior bladder
 Secrete fluids and substances
which constitute 60% of semen
 Their ducts join vas deferens
 Sperm and seminal fluid mix
in ejaculatory duct
 Prostate: note here and next
slide
 Bulbourethral glands
 Secrete mucus during sexual
excitement and ejaculation 13
(lubricant)

14. The Prostate
 Size & shape of a chestnut
 Encircles 1st part of urethra
 3 types of glands
 Contribute to semen (milky
fluid and enzymes)
 PSA measured as indicator
of prostate cancer (“prostate
specific antigen”)
 Fibromuscular stroma
14

15. Posterior view  Male external genitalia
 Scrotum
 Penis
 Penis: 3 parts
 Root (attached)
 Free shaft or body
 Enlarged tip called glans penis
 Skin of penis is loose
 Prepuce or foreskin
 Cuff around glans
 Removed if circumcision
 See cross section, penis
 Urethra (called spongy or penile urethra
here)
 3 erectile bodies (parasympathetic
stimulation during sexual excitation
causes engorgement with blood allowing
erection):
 Corpus spongiosum
 Pair of corpora cavernosa
 Vessels and nerves
 Ejaculation caused by sympathetic
nerves
 Contraction of smooth muscle of ducts
and penis
15

16. Review pics
16

17. The Female Reproductive System
 Production of gametes (ova, or eggs)
 Preparation for support of developing
embryo during pregnancy
 Cyclic changes: menstrual cycle
 Averages 28 days
 Complex interplay between hormones and
organs: at level of brain, ovaries and uterus
17

18.  Gonads: the ovaries
 Paired, almond-shaped,
flanking the uterus in
lateral wall of true pelvis
 3 x 1.5 x 1 cm in size Posterior view
18

19. Anterior view
Ovaries are
retroperitoneal,
but surrounded
by peritoneal
cavity
Held in place by
mesentery and
ligaments:
•Broad ligament
•Suspensory
ligament of the
ovary
•Ovarian
ligament
Innervation:
•Sympathetic
and
parasympathetic
19

20. Structure of ovary
 Fibrous capsule is called tunica albuginea
 Outer cortex houses developing gametes the
oocytes, within follicles
 Inner medulla is loose connective tissue with largest
vessels and nerves
20

21. The Ovarian Cycle
 Follicular phase
 1st approx 14 days but variable
 Egg develops in a follicle
 Stimulated by FSH (see next
slide)
 Estrogen produced
 Ovulation
 Egg released from follicle (LH
surge)
 Egg in abdominal cavity
 Picked up by fimbria of fallopian
tube
 Not necessarily halfway point
 Luteal phase
 Postovulatory phase 14 days
(more constant)
 Corpus luteum develops from
exploded follicle
 Produces progesterone as well
as estrogen
 Progesterone stimulates
uterus to be ready for baby
 If no pregnancy, corpus luteum
degenerates into corpus 21
albicans

22. Nearly mature follicle
 Oocyte develops the zona pellucida
 Glycoprotein coat
 Protective shell (egg shell)
 Sperm must penetrate to fertilize the oocyte
 Thecal cells stimulated by LH to secrete androgens
 Granulosa cells (with FSH influence) convert androgens to
estrogen (follicular cells called granulosa cells now)
 Clear liquid gathers to form fluid-filled antrum: now a
secondary follicle
 Surrounding coat of granulosa cells: corona radiata
 Fully mature, ready to ovulate, called: ”Graafian follicle”22

23. Ovulation
 Signal for ovulation is
LH surge
 Ovarian wall ruptures
and egg released,
surrounded by its
corona radiata
23

24. Oogenesis
Generation of eggs
 Starts in fetal period
 No more oocytes made
after about 7th month
 Developed only to early
stage of meiosis I by birth
and stops (called primary
oocyte)
 6-12 primordial oocytes
each cycle selected to
develop for ovulation (most
die)
 Only then is meiosis I
completed
 Secondary oocyte is then
arrested in meiosis II
 Meiosis II not completed
(now an ovum) unless
sperm penetrates its plasma
membrane
 Of the 4 daughter cells, only
one becomes ovum (needs
a lot of cytoplasm)
 The other 3 become “polar
bodies” 24

25. Fallopian (uterine) tubes, AKA oviducts
____Fallopian tubes__ Fimbriae (fingers) pick
up egg
Fimbriae *
Beating cilia and
muscular peristalsis
propel egg to uterus
Empties into superior
part of uterus*
Enlargement of
mucosa layer
showing ciliated
columnar
epithelium
Cross section
through entire
tube
PID
25

26. The Uterus (womb)
 In pelvis anterior to rectum and posterosuperior to
bladder
 Hollow, thick-walled organ
 Receives
 Retains Uterus is pear-shaped
 Nourishes fertilized egg=embryo (before babies)
Usually anteverted, can
be retroverted
26

27. Parts of uterus:
Body (major part)
Fundus
Isthmus
Cervix
Cavity of uterus
small (except in
pregnancy)
Cervical canal
•Internal os
•External os
Vagina
Cervix
•Tough, fibrous ring
•Inferior tip projects
into vagina
27
•Produces mucus

28. The Uterine Wall*
 Three basic layers
 Perimetrium: outer serous membrane
 Myometrium: middle muscle
 Endometrium: inner mucosal lining
Uterine
supports:
•Mesometrium
(largest division
of broad lig) – *
main support
•Cardinal
ligament
•Round ligament
(Prolapse) 28

29. Endometrium (inner mucosal lining of uterine cavity)
 Simple columnar epithelium containing secretory
and ciliated cells
 Lamina propria of connective tissue Note:
Uterine glands
Uterine arteries
2 main layers (Strata)
1. Functionalis (functional layer)
2. Basalis (basal layer)
(shed if no implantation
of baby)
(not shed)
29

30. Time: one cycle (approx 28 d.)
ovulation
*  Pituitary hormones
 FSH: follicle
stimulating hormone
 LH: luteinizing
hormone
Follicular phase Luteal phase
 Ovarian hormones
 Estrogen
 Progesterone
30

31. The cyclic changes of uterine wall and
follicle
(hormone graphs should be above)
If no baby, decreasing
progesterone - slough
Proliferative Secretory phase: vascular
phase: rebuilds rich glands enlarge: will
itself after slough sustain baby (needs
progesterone: corpus luteum 31
initially then placenta)

32. (inhibin: inhibits pituitary
secretion of FSH)
32

33. The
Vagina
 Thin-walled
tube
 Inferior to
uterus
 Anterior to
rectum
 Posterior to
urethra &
bladder
 “Birth canal”
 Highly
distensible
wall: 3 layers
 Adventitia
 Muscularis
 mucosa
33

34. External female genitalia aka vulva or pudendum
 Mons pubis: fatty pad over pubic symphysis, with hair after puberty
 Labia (lips) majora: long fatty hair-covered skin folds
 Labia minora: thin, hairless, folds enclosing vestibule
 Vestibule: houses external openings of urethra and vagina
 Urethra is anterior (drains urine from bladder)
 Baby comes out through vagina (vaginal orifice in pic)
 Clitoris: anterior, homolog of penis (sensitive erectile tissue)
 Perineum: diamond shaped region
34

35. Mammary glands (breasts)
 Modified sweat glands
 Both sexes but function (normally) only in lactating female
 Produce milk to nourish baby
 Respond to hormonal stimulation
 Lymph drains into parasternal and axillalry lymph nodes
 Nipple surrounded by pigmented ring of skin, the areola
 Muscles underneath: pectoralis major and minor, parts of serratus anterior
and external oblique
35

36.  Mammary glands consist of 15-25 lobes
 Each a distinct compound alveolar gland opening at the nipple
 Separated by adipose and suspensory ligaments
 Smaller lobules composed of tiny alveoli or acini
 Like bunches of grapes
 Walls: simple cuboidal epithelium of milk-secreting cells
 Don’t develop until half-way through pregnancy (ducts grow during puberty)
 Milk passes from alveoli through progressively larger ducts
 Largest: lactiferous ducts, collect milk into sinuses
36

37. Conception
 After ejaculation into the vagina, sperm swim to meet an egg
 Sperm live 5-7 days (need cervical mucus)
 Eggs live about 12-24 hours, so conception only occurs during this short window
 Fertilization occurs in the fallopian tube
Events leading to
fertilization:
•Sperm binds to receptors on
zona pellucida
•Acrosomal reaction –
enzymes digest a slit
•Sperm passes through zona
•Fusion of a single sperm’s
plasma membrane with
oocyte’s plasma membrane
•Cortical reaction: sperm
receptors destroyed in zona
so no more enter; sperm
nucleus engulfed by egg’s
cytoplasm
Fertilization occurs
at the moment the
chromosomes from
the male and female 37
gametes unite

38. Initial days
 Cleavage (cell division)
 Blastocyst stage by day 4: now in uterus
38

39. Implantation
Blastocyst floats for 6-9 days post
2 days: “hatches”
by digesting zona conception -
enough to squeeze burrows into
out endometrium
39

40. Formation of Placenta
Both contribute:
•Trophoblast from embryo
•Endometrial tissue from mother
Not called placenta until 4th month
Embryonic
blood
circulates
within chorionic
villi, close to
but not mixing
with mother’s
blood
•Nutrients
to baby
•Wastes to 40
mom

41. The “Placental Barrier”
 Sugars, fats and oxygen diffuse from mother’s blood to
fetus
 Urea and CO2 diffuse from fetus to mother
 Maternal antibodies actively transported across placenta
 Some resistance to disease (passive immunity)
 Most bacteria are blocked
 Many viruses can pass including rubella, chickenpox,
mono, sometimes HIV
 Many drugs and toxins pass including alcohol, heroin,
mercury
 Placental secretion of hormones
 Progesterone and HCG (human chorionic gonadotropin, the
hormone tested for pregnancy): maintain the uterus
 Estrogens and CRH (corticotropin releasing hormone): promote
labor
41

42.  Gestational period: averages 266 days
Childbirth 
(this is time post conception; 280 days post LMP)
Parturition: the act of giving birth: 3 stages of labor
1. Dilation: 6-12h (or more in first child); begins with regular uterine
contractions and ends with full dilation of cervix (10cm)
2. Expulsion: full dilation to delivery – minutes up to 2 hours
3. Placental delivery: 15 minutes
Dilation of cervis; head enters true pelvis Expulsion: head first safest as is largest part
Delivery of the placenta
Late dilation with head rotation to AP position 42

43. Stages of Life
 Embryologically, males and females start out
“sexually indifferent”
 Gonads, ducts and externally identical structures
 At 5 weeks gestation changes start to take place
 Puberty: reproductive organs grow to adult size
and reproduction becomes possible
 Between 10 and 15
 Influence of rising levels of gonadal hormones
 Testosterone in males
 Estrogen in females
 Female menopause (between 46 and 54):
 Loss of ovulation and fertility
43

44. 44

45. 45

46. 46