3. SECONDARY SEXUAL
CHARACTERISTICS
The external characteristics which
differentiate men from women are
called secondary sexual
characteristics.
During puberty between the ages of
eleven and fifteen the reproductive
system matures.Some physical
changes are the same for both sexes,
like growing taller or hair growing in
the armpit.
4. Other changes are specific to each sex:
Girls develop breasts and their hips
get wider.
Boys get deeper voices or get facial
hair.
5. REPRODUCTIVE CELLS
Reproductive cells carry out the funtion
of reproduction.
Sperm: are the male reproductive
cells. They have a head and a long tail
called flagellum. They are produced in
large numbers from the time of
puberty.
Ova: are the female reproductive cells.
They do not move. From puberty an
ovum matures every month.
9. FERTILISATION
Fertilisation occurs when an ovum and a sperm
join inside the fallopian tubes and they create a
single cell called zygote. The zygote goes down
the fallopian tubes, it is implanted in the wall of
the uterus and it becomes an embryo.
10. PREGNANCY AND BIRTH
PREGNANCY
Pregnancy last about 9 months and
ends in a birth.
During the early stages, different
structures are created to protect the
embrio:
The placenta.
The umbilical cord.
The amniotic sac.
11. The baby develops step by step:
After 3 months: the embryo has all its
organs. It becomes a foetus.
After 5 months: the baby starts moving
and the mother feels it.
After 9 months: the baby is ready to be
born and it weighs around 3 kilos.
LABOUR
o Dilation.
o Expultion.
o Afterbirth.
