The female reproductive system produces eggs in the ovaries and transports them through the fallopian tubes. If an egg is fertilized by sperm, it implants in the uterus and develops into a fetus with support from the placenta and umbilical cord. The male reproductive system produces sperm in the testes which are transported and stored until ejaculation. Fertilization normally occurs when sperm meet and penetrate an egg in the fallopian tubes.

1. 6. Human Physiology
6.6 Reproduction

2. Female reproductive system
Ovaries : egg cells are
produced. Within the ovaries,
each developing egg cell is
contained inside a follicle.
Oviduct (also called a fallopian
or uterine tube): narrow tube
about 10 cm long, which serves
as a passageway to the uterus.
It is normally the site of
fertilization.
Uterus: a hollow, muscular organ
with thick walls. If an egg is
fertilized by a sperm cell, the
uterus functions to contain and
protect the developing baby.
Cervix: connects the uterus to
the vagina.
Vagina: has several functions: it
receives the penis and sperm

3. Male reproductive system
Testes: Sperm cells begin their
development
Scrotum: a sac-like structure that
contains the testes. One function of the
scrotum is to house the testes outside
the main body cavity, a location that is
1° to 3°C cooler than normal body
temperature.
Epididymis: Sperm complete their
development and are stored in a long,
thin, coiled tube attached to each testis.
Seminal vesicles, prostate gland, and
bulbourethral glands: secrete fluids that
function in the transport and survival of
sperm: semen.
Vas deferens: connecting ducts.
Muscular contractions propel sperm
from the epididymis through the urethra.
Penis: an organ consisting mainly of

4. Development of gametes

5. Development of egg cells
 By the time a human female
reaches puberty her ovaries contain
about 400,000 follicles. Each follicle
contains a resting primary oocyte.
 Ovulation: approximately every 28
days, hormones cause one follicle
and the oocyte within it to mature,
commonly called ovule. When the
follicle breaks open, the secondary
oocyte is released.
 Meiosis II is not completed unless
the egg is penetrated by a sperm
cell. As soon as this occurs, the
secondary oocyte undergoes its
final meiotic division. This forms the
ovum, the mature egg cell with a
haploid nucleus that is capable of
fusing with the sperm nucleus.

6. Development of sperm cells
 The development of sperm cells
begins when males reach
puberty.
 The process begins with the
primary spermatocyte within the
testis that undergoes meiosis and
produces four haploid sperm
cells.
 Sperm cells move from the testes
to the epididymis where they
complete their development. A
mature sperm has a tail
(flagellum) that enables it to swim
within the female reproductive

7. Hormonal control in females
• Sexual maturity in women is
marked by the beginning of the
menstrual cycles. These cycles
coordinate the development and
release of an egg with the
conditions required in the uterus
to support a pregnancy.
Anterior pituitary hormones
• The cycle is controlled by
hormones from the brain (FSH
and LH) and the ovary (estrogen
and progesterone).
• FSH and LH are two hormones
Ovarian hormones that are active at significant
phases of human development
including primary and secondary
sexual characteristics. They are
both significant hormones in the

8. http://kidshealth.org/misc/movie/bodybasics/bodybasics_female_repro.html
http://www.sumanasinc.com/webcontent/animations/content/ovarianuterine.

9. (d)
(a) (e)
(b) (g)
(g) (c) (f)
(d)
(g)
(a) FSH is secreted by the pituitary gland of the brain and stimulates the development
of a primary follicle.
(b) Primary follicle cells secrete estrogen which in turn increase the secretion of FSH in
a positive feedback.
(c) The estrogen thickens the lining of the uterus in preparation for a fertilized egg.
(d) The peak of estrogen secretion at day 12 causes the pituitary to release a surge of
LH. This loosens the now mature egg which is released in ovulation
(e) Progesterone and estrogen together stop any more LH and FSH being secreted
from the pituitary. (negative feedback) – This prevents further follicle development or
ovulation.
(f) Progesterone maintains the lining of the thickened endometrium in preparation for
the implantation of a fertilized egg.
(g) If implantation does not take place then the Corpus luteum degenerates and

11. Hormonal regulation in males
Roles of testosterone in
males
1. Week 7 of embryonic
development, testosterone initiates
the development of male genitalia.
2. Puberty: testosterone initiates the
development of secondary sexual
characteristics:
- increase in muscle mass
- increase in the length of the long
bones (height)
- increase in the length of the vocal
cords (voice deepens)
- spermatogenesis
- growth of the penis and testis
3. Post puberty testosterone
maintains the production of sperm

12. In Vitro Fertilization (IVF)
 IVF is a method where the eggs are removed from the
ovaries to be fertilized in the laboratory.
 The eggs are then cultured for approx. 2 days and
nights before the fertilized egg is transferred to the
uterus for normal growth.
 At IVF the woman’s ovaries are stimulated to produce
more and bigger eggs than at a normal cycle. This
means that more than one egg can be removed for
the treatment. More eggs improve the probability of
finding suitable eggs for fertilization.
 IVF treatment is recommended in those cases where
the woman has tubal blockage, the man has a poor
sperm quality, or the cause of infertility is unexplained.
There are a number of different medications for IVF
treatment, which are to be adjusted to the individual
need.

13. In Vitro Fertilization (IVF)
a) FSH and LH are given to stimulate multiple egg cell releases
b) Eggs are collected from the ovaries
c) Eggs are fertilized with father’s sperm in a dish or tube and it’s incubated.
d) After incubation, viable blastocysts are selected and developed into embryos
e) Usually 3 embryos are selected for implantation. Usualle one or more will be
successful, hence the risk for multiple pregnancy
f) After a month of rest, a woman can take a pregnancy test. If it did not
succeed, she can wait a few months to try again.
(a)
(b)
(c)
(d) (e)

14. IVF
 Treatment with in vitro fertilization implies that:
 The man produces sperm cells, or has sperm
cells that we in special cases can extract from the
testicle or from the epididymis. If the man does
not produce sperm cells, donor sperm cells can
be used.
 The woman has ovulation, either by herself or
through hormone treatment.
 The woman has a normal uterus.
 The couple has no incidence of venereal
diseases or infections.
 You have received genetic counseling.

15. Ethical issues associated with
IVF
 FOR  AGAINST
 Right to have children  Risk of mother and
 Provide a family for
fetuses of multiple
radiation, chemo pregnancy
therapy cancer  Can be expensive
patients.  Emotional cost of
 Medical advances failure can be high
make it safer every  Does termination of
time human embryos count
 Unused embryos can as ending a human
be stored (frozen) for life?
later use, donated for  Religious: are we
research or as a playing ‘God’?
source of stem cells

16. Natural fertilization
 Fertilization occurs when the egg and sperm cells
fuse. When a sperm cell penetrates the egg,
meiosis II is completed and the ovum is formed.
Within the ovum, the nuclei of the sperm and
ovum fuse, forming a diploid nucleus. This
fertilized egg cell is called a zygote.

17. Human development, first trimester
 Approximately three weeks after
fertilization, gastrulation takes place. It forms
three cell layers: ectoderm, endoderm, and
mesoderm. The ectoderm (outer layer) forms the
outer part of the embryo's skin and the central
nervous system. The endoderm (inner layer)
forms the digestive tract and lungs. The
mesoderm (middle layer) forms most of the other
organs.

18.  Soon after implantation, trophoblast cells and
cells from the uterus form the placenta.
 This structure enables nutrients and waste
products to be transferred between the mother
and developing baby.
 By the end of the third month, the placenta is fully
formed and functional. In the wall of the placenta,
the mother's blood and baby's blood remain
isolated in separate circulatory systems.