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Chapter 10 – Human Reproduction
Fallopian
tube
The male reproductive system
Gland which
makes
seminal fluid
Ovary
Vagina
Sperm
duct
Penis
Uterus
Ovary
Produces egg cells.
Produces sex hormones.
Testis
Testis
Makes sperm cells and sex
hormones.
Fallopian
tube
Carries the egg from the
ovary to the uterus.
Sperm
cell
Made in testes. The male
gamete (sex cell)
Vagina
Holds the penis during
intercourse.
Sperm
duct
Carries the sperm cells from
the testes.
Uterus
Also called the womb.
Holds and protects the
baby during pregnancy.
Glands
Produce fluids for the sperm
cells to move about in and also
food supply.
Cervix
Opening of the uterus.
Puberty – The time between the ages of
10 and 15 when hormone changes, in both
boys and girls, cause the body to mature.
In boys
 Voice deepens
 Growth of hair on face, chest, and
underarms.
 Sex organs mature.
 Sperm cells made.
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In girls
 Breasts develop, Growth of body
hair, Eggs mature and released,
Periods start and menstrual cycle
starts.
The menstrual cycle
From early teenage years up to the
menopause, in her late forties, a woman
will undergo a series of monthly changes,
which will affect her reproductive
system and her health and well-being
generally. This series of monthly changes
is often referred to as her menstrual
cycle. The menstrual cycle occurs in a
number of stages.
The fertile period
This is the time in the month in which a
woman is most likely to become pregnant
if she has sexual intercourse.
 Sperm cells can survive for 3 days.
 Egg cells can survive 4 days.
 If a woman has sexual intercourse
three days before ovulation the
sperm cells may still be viable
when the egg appears in the tube.
 If she has sexual intercourse up
to four days after she ovulates,
the egg may still be viable and
pregnancy may occur.
 This means that there is a time
from about day 11 up to day 18
when she is most fertile i.e. The
fertile period.
1. Menstruation
2. Repair stage
(period)
Day 1 – 5
Day 6 – 13
 Shedding of
 Extra lining
extra lining of
builds up on the
the uterus.
uterus.
 Blood loss.
 Unfertilised egg
passed out.
4. Rest stage
However, this assumes that the egg is
released at precisely the same time each
month. But this not always the case, it
can be early or late. So there is no
definite way of telling.
How a baby is made
1. Sexual intercourse
 During intercourse, the man’s
becomes filled with blood. This
causes an erection which allows
the penis to be placed inside the
vagina.
 A mixture of sperm cells and
seminal fluid (semen) is ejaculated
from the penis at the opening of
the uterus, the cervix.
3. Ovulation
Day 15 – 28
Day 14
 The extra
 The egg is
lining stays built
released from
up in case
the ovary into
fertilisation
the fallopian
occurs.
tube.
2. Fertilisation
 The sperm cells, 200 million of
them, swim up through the uterus
towards the fallopian tube.
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


Only a few thousand make it to
the egg.
Several sperm cells surround the
egg cell but only one fertilises it.
Fertilisation is the fusion of the
male sperm cell and the female
egg cell to form a zygote.
Fertilisation takes place only in
the fallopian tube.



It gets all its food and oxygen
through and umbilical cord and
placenta.
Wastes and carbon dioxide also
pass out this way.
In this way the baby continues to
grow until birth
4. Birth
 The birth process begins with
contractions of the uterus
(labour).
 The amniotic sac bursts and the
contractions increase in severity.
 The mother must push with the
contractions to push the baby out.
 Eventually, the baby will be born,
head first.
 The umbilical cord is cut and
clamped.
 The placenta passes out shortly
afterwards.
3. Pregnancy
 Once fertilisation occurs the
woman’s periods will stop and she
will not menstruate until after the
baby is born.
 Pregnancy lasts, on average, 40
weeks.
 After a week, the baby is a ball of
200 cells, and implants itself
(buries itself) in the wall of the
uterus (this where the extra lining
is needed).
 For the next 40 weeks the baby
gets all it needs from its mother
with the help of this lining.
 After 8 weeks the baby is a fully
formed, but miniature, version of
a new-born baby.
Fertilisatio
n occurs
here
Baby grows
here

Egg is
released from
here
The baby is held in a fluid-filled
sac (called the amniotic sac)
which protects it.
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Genetics

Genetics is the study of the
inheritance of characteristics. Many
of our physical characteristics are
passed from generation to generation
e.g. hair colour, eye colour, height
etc.

The nuclei of ordinary human body
cells contain 46 chromosomes, found
as 23 pairs of chromosomes.

These chromosomes are chemicals
which appear as thin threads in the
nucleus, when viewed under the
microscope. They are made of
protein and a chemical called DNA.

Each chromosome is divided into
segments called genes. Each gene
controls a different characteristic.
Genes



Chromosome
Genes can be dominant or recessive.
A Dominant gene always shows in the
physical appearance of the person.
A recessive gene is hidden if the
dominant gene is present.
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