I.Male Reproductive System

Organs: testes, ducts, glands & supporting
structures

Supporting structures include scrotum & penis
Ducts: epididymis, ductus deferens,
ejaculatory ducts & urethra
 Glands: seminal vesicles, prostate,
bulbourethral glands

Figure 23.1
A. Scrotum
Pouch that supports the testes
 Septum separates into separate sections for
each testis
 Sperm requires temperatures 2-3oC below
body temperature
 allows raising and lowering testes to adjust
temperature

B. Testes

Paired oval glands
200-300 lobules containing seminiferous
tubules
 Sperm producing cells and nurse cells
(protect sperm)

C. Epididymis
Stores sperm before ejaculation
 Comma shaped on top of testes

Figure 23.2a
Figure 23.2b
D. Spermatogenesis

Occurs in seminiferous tubules


Cell types involved: spermatagonia, sertoli cells & interstitial
cells (leydig cells)
move into->epididymis
Spermatogenesis stages
 Takes
~65-75 days from first division
to release

~300 million /day

Life span ~ 48 hrs in female tract
Figure 23.3
E. Sperm
Structure: Head, middle, tail
 tail- flagellum = motility
 Middle - mitochondria = energy
 Head-chromosomes + acrosomal cap
 acrosome-enzymes-> penetrating egg

Figure 23.4
F. Sperm route


Testes ->Epididymis vas (ductus) deferens
 urethra
G. Semen
2.5-5 ml per ejaculation
 50-150 million sperm per ml
 When number falls below 20 million/ml –
sterile
 7.2-7.7 ph

H. Accessory Glands

Seminal vesicles- seminal fluidFructose (sperm ATP production
 + alkalinity (neutralize acid in tracts)
 60% of ejaculate


Prostate- surrounds upper urethra
Increases volume + adds antibiotics
 Citric acid for energy
 25% of ejaculate


Bulbourethral glands:
More alkalinity + mucus fluid
 Pre ejaculate
 10 % of ejaculate

I. Penis
 Contains
urethra-
 Passage
 Glans
for semen & urine
has external urethral oriface
 Uncircumcised glans covered by
prepuce
Figure 23.6
II.Female Reproductive
System

Ovaries: paired organs- produce
secondary oocytes ova (after fertilization)
 Hormones: progesterone & estrogens
 From same embryonic tissue as testes

uterine (fallopian) tubes & uterus
 vagina
 External organs (vulva or pudendum)

A. Histological Structure of
Ovary



Germinal epithelium- covers surface
Ovarian cortex: connective tissue containing
follicles
Follicle; oocyte + surrounding cells




Surrounding cells nourish oocyte & produce
hormones
Grows during maturation 
Graafian follicle ovulation
Post ovulation  corpus luteum

Progesterone, relaxin & inhibin
Figure 23.6
Figure 23.7
B. Uterine Tubes
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

C. Uterus
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

Vagina






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
Figure 23.9
Perineum & vulva (cont.)

Clitoris- small cylindrical mass of erectile
tissue & nerves


Also contains prepuce & glans
External urethral oriface- anterior to
vaginal oriface
Female Reproductive
Cycle



20-34 days- cycles in both ovaries & uterus
Ovarian cycle= maturation of follicle, ovulation &
corpus luteum formation
Uterine Cycle= menstrual cycle



controlled by hormones from ovary
Estrogens growth of endometrium Progesterone
supports endometrium for implantation
Combine cycles = Reproductive cycle
Figure 23.12
Hormonal Regulation






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

Gonadotropin releasing hormone= GnRH

Comes from hypothalamus and stimulates
the release of FSH from pituitary.
Hormones

FSH – Follicle stimulating hormone
Follicle stimulated to start maturing an egg
 Starts to rise at the end of the cycle and during
menstruation. An egg starts to mature.
 Spikes during ovulation


LH- Lutenizing hormone
Peaks as estrogen peaks
 Helps to cause ovulation

Hormones

Estrogen:




Development & maintenance of reproductive
structures & secondary characteristics
Tells the uterine lining to build up
From follicle
Progesterone



maintains uterine lining for implantation
Prepares breast for milk production
From corpus luteum

hCG- human chorionic gonadotropin
Made by embryo
 Tells corpus luteum to keep making
progesterone to maintain lining

Relaxin= relaxes uterus- inhibits
myometrium
 Inhibin- inhibits FSH release

Phases of Cycle

Menstrual phase: ~1st 5 days of cycle



Several Ovarian follicles enlarge
Decreased progesterone & estrogen uterine arteries
constrict endometrium sloughs off
Preovulatory- between menstruation & ovulation


Ovaries: follicles grow & secrete estrogen & inhibin one
dominates
Uterus: growth of new endometrium
Phases of Cycle (cont.)

Ovulation


Release of 2o oocyte with LH surge
PostovulatoryOvaries: follicle collapses corpus luteum
(luteal phase)
 If no fertilization  FSH & LH  corpus
albicans & decreased Progesterone 
menstruation

Phases of Cycle (cont.)
If fertilization & division human chorionic
Gonadotrophin (hCG) stimulates corpus
luteum secretion
 Uterus: Progesterone & estrogens
complete development of uterus for
implantation

Figure 23.13