UNIT 3. REPRODUCTION

1. UNIT 3:
REPRODUCTION

2. 1. HUMAN REPRODUCTIVE
CELLS
There are two types of human reproductive
cells:
- The female egg cell (ovum)
- The male sperm cell (spermatozoon)
Human beings, like many animals, reproduce by
sexual reproduction.

3. FEMALE REPRODUCTIVE CELLS
During puberty, a girl`s ovaries start to release eggs.
Every 28 days, a mature egg cell released from one of
the ovaries. (menstrual cycle)

4. MALE REPRODUCTIVE CELLS
During puberty, a boy`s body starts to produce sperm
cells. Millions of sperm cells are produced in the
testicles throughout a man`s lifetime.

5. UTERUS
Here a fertilised egg cell
develops into a fetus
CERVIX
Is the part of the uterus that
leads to the vagina
OVARIES
They produce egg
cells.
FALLOPIAN
TUBES
They connect the
ovary with the
uterus. The egg
cell travels along
them.
VAGINA
It is a muscular canal from the
uterus to the vulva.
2. THE FEMALE REPRODUCTIVE
SYSTEM

6. The menstrual cycle

7. TESTICLES
They produce sperm
cells.
They are inside a
bag of skin called
scrotum.
URETHRA
Is a tube that carries both
semen and urine out of
the body
3. THE MALE REPRODUCTIVE
SYSTEMVAS DEFERENS
Is a tube that
connects the testicles
to the seminal
vesicles, prostate and
urethra.
PENIS
Is an elastic organ with a
cylindrical shape
PROSTATE
It produces a white
liquid that makes up
the semen
SEMINAL VESICLES
They produce a liquid
that becomes part of
the semen

8. 4. WHAT`S FERTILISATION?
When a sperm cell joins with an egg cell in the
fallopian tube, they form a new cell called a
zygote. This process is called fertilisation.
After about six days the zygote goes into the
uterus and becomes attached to the wall of the
uterus. It divides many times to form a group of
cells called an embryo.
After about nine weeks the embryo develops into
a fetus.

10. PREGNANCY
Pregnancy is the period between the fertilisation
and the birth of a baby. (9 months)
During pregnancy two organs form inside the
uterus.
The amniotic sac
is a thin bag that
contains the
amniotic fluid.
This liquid protects
the fetus.
The placenta
provides the fetus with
oxygen and nutrients
from the mother
blood. The fetus is
connected to the
placenta by the
umbilical cord.

11. THE BIRTH
During birth, the walls of the uterus start to
contract. The amniotic sac breaks and the
contractions push the baby into the vaginal
canal.
Little by little the baby is expelled through the
vagina. The amniotic sac, the placenta and the
rest of the umbilical cord are expelled too.

12. 5. MEDICAL ADVANCES IN
REPRODUCTION
IN-VITRO FERTILISATION
The reproductive cells are joined
outside the woman`s body, in a
laboratory. Then, the zygote is
placed inside the woman`s uterus.
AMNIOCENTESIS
A small amount of amniotic fluid
is removed from the amniotic sac.
It is analysed to detect some
abnormalities.
CESAREAN
Occasionally problems can occur
during birth (for example, a
breech birth). Sometimes, the
fetus is extracted through a small
opening in the abdomen.
ULTRASOUND SCAN
It is used to check the
development of the fetus.