This presentation contains the human reproductive system. It discusses the parts and functions of major organs, embryological development after fertilization.

1. Reproductive System
By: Mr. Nikko Lorenz Lawsin

2. Reproduction
Sexual reproduction a.k.a Genetic
Recombination.
- fusion of gametes
Asexual reproduction a.k.a Genetic Duplication
- One parent clones the offspring
Many invertebrates reproduce asexually by fission
= separation of a parent into two or more
individuals of about the same size.

3. Asexual Reproduction
Budding = new individuals arise from outgrowths of
existing ones.
Fragmentation = breaking of the body into pieces,
some or all of which develop into adults.
Fragmentation must be accompanied by
regeneration = regrowth of lost body parts.
Parthenogenesis is the development of a new
individual from an unfertilized egg.

4. Asexual Reproduction
Budding = new individuals arise from outgrowths of
existing ones.
Fragmentation = breaking of the body into pieces,
some or all of which develop into adults.
Fragmentation must be accompanied by
regeneration = regrowth of lost body parts.
Parthenogenesis is the development of a new
individual from an unfertilized egg.

5. In external fertilization, eggs shed by the
female are fertilized by sperm in the
external environment.
In internal fertilization, sperm are deposited
in or near the female reproductive tract,
and fertilization occurs within the tract.
Internal fertilization requires behavioral
interactions and compatible copulatory
organs.
External vs Internal Reproduction

6. To reproduce sexually, animals must have
systems that produce gametes.
In most species individuals have gonads =
sex organs that produce gametes.
Some simple systems do not have gonads,
but gametes form from undifferentiated
tissue.
Key Concepts

8. Comparison of Reproductive System
Points of
Comparison
Male Reproductive
System
Female Reproductive
System
1.Copulatory
Organ
Penis Vagina

9. Comparison of Reproductive System
Points of
Comparison
Male Reproductive
System
Female Reproductive
System
2.Gonads
(gametes-
forming organ)
Exocrinic
 Endocrinic
Testes
Forms
sperm/spermatozoa
Forms Testosterone and
androgens
Ovary
Forms ovum
Forms Estrogen and
progesterone and
androgen
Ovulation is the release of mature
eggs at the midpoint of a female
cycle.

10. Comparison of Reproductive System
Points of Comparison Male Reproductive System
3.Reproductive
Ducts and glands
Where semen travels
Epididymis (coiled tube),
Vas deferens,
Seminal vesicle (gives nutrients
to sperms),
ejaculatory duct,
prostate gland (maintains the
pH and alkalinity of the sperm),
Cowper’s gland/Bulbourethral
gland (maintains the
viscosity/mucoid of the sperm),
Urethra and Urethral opening

11. Comparison of Reproductive System
Points of Comparison Female Reproductive System
3.Reproductive
Ducts and glands Fallopian tube – site of
fertilization
Uterus – muscular wall (smooth
muscle), expandable where
implantation of embryo takes
place.
Cervix – receive and entrance
of sperms and it can only be
open during giving birth.

15. Control by hypothalamus Inhibited by combination of
estradiol and progesterone
Stimulated by high levels
of estradiol
Inhibited by low levels of
estradiol
Hypothalamus
GnRH
Anterior pituitary
FSH LH
Pituitary gonadotropins
in blood
LH
FSH
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation
Ovarian cycle
Growing follicle Maturing
follicle
Corpus
luteum
Degenerating
corpus luteum
Follicular phase Ovulation Luteal phase
(a)
(b)
(c)
Days
0 5 10 14 15 20 25 28
| | | | | | | |
–
–
+

16. Ovarian hormones
in blood
Peak causes
LH surge
Estradiol level
very low
Estradiol Progesterone
Ovulation Progesterone and estra-
diol promote thickening
of endometrium
Uterine (menstrual) cycle
Endometrium
0 5 10 14 20 25 28
| | | | | | | |
Days
15
Menstrual flow phase Proliferative phase Secretory phase
(d)
(e)

24. Types of Twinning