Reproduction

Learning Objectives:

• To describe and explain the fertilisation of an egg in human reproduction.

Starter:

• How do we get babies?

Fertilisation in HumansTo put it simply, it’s an “egg and sperm race”…

Egg

Sperm

Fertilisation

Eggs and spermThe female egg cell and the male sperm cell are examples of ____________ cells:

The egg cell is basically an enlarged cell with massive _____ reserves

The ______ cell is specialised in two ways:

Words – food, swimming, sperm, specialised, digest

Head packed with “enzymes” to ______ its way through the egg

Strong tail for ________

Nucleus

Male reproductive system

Female reproductive system

What is the first stage in becoming pregnant?

Fertilisation normally happens in the oviduct. The fertilised egg then passes along the oviduct into the uterus and IMPLANTS into the thick, soft lining.

While this is happening the cell begins to divide. 2 then 4 then 8 ….. cells

FERTILISATION

Fertilisation and implantation

The fertilised cell replicates by Mitosis

Each cell is identical up to the 32 cell stage and after that it is known as

an Embryo

1st and 2nd Division

From embryo to foetus – animation

Inside the womb

Placenta – allows the mother’s blood to come close to the baby’s to allow exchange of food, oxygen and wastes by diffusion. The placenta also has a large surface area.

5 Weeks

6 Weeks

7 Weeks

8 Weeks

3 Months

4 Months

6 Months

4 weeks 9 weeks 20 weeks 40 weeks

In order for the embryo to survive and grow it needs nutrition and for waste products to be removed.

The PLACENTA is the link between the baby and the mother. The two blood supplies run very close to each other to allow waste products and useful substances to pass between the baby mother.

The baby is linked to the PLACENTA by the UMBILICAL CORD

Foetus

Uterine wall

????

AMNIOTIC FLUID surrounds the foetus as it grows in the uterus and provides protection by cushioning the foetus

How does the baby get out?

The uterus is made of strong muscle. When the baby is fully grown (40 weeks in humans) the uterus begins to CONTRACT pushing the baby out.

Birth animation.

The baby is no longer linked to its mother by the placenta. What will it have to start doing on its own to survive?

Giving birthThe following events happen when a woman is about to give birth:

1) The amniotic sac bursts (“water breaking”)

2) Muscles in the uterus wall start contracting to push the baby out

3) The muscles in the cervix relax and widen

Glue the diagram in to your bookGlue the diagram in to your book- add labels and descriptions- add labels and descriptions

Question: Why is it important for a mother to lead a healthy lifestyle while they are pregnant?

What sort of things should they avoid doing?

A. During labour, hormones make the muscles of the uterus contract at regular intervals.

 B. Contractions continue until the placenta has passed out of the

mother’s body. C. The muscles of the cervix relax and the head of the baby passes

into the vagina. D. The baby turns so that its head is above the cervix, ready for birth.

E. The contractions of the uterus push the baby out through the vagina.

 F. The amnion splits and the watery amniotic fluid runs out.

A. During labour, hormones make the muscles of the uterus contract at regular intervals.

 

B. Contractions continue until the placenta has passed out of the mother’s body.

C. The muscles of the cervix relax and the head of the baby passes into the vagina.

 

D. The baby turns so that its head is above the cervix, ready for birth.

E. The contractions of the uterus push the baby out through the vagina.

 

F. The amnion splits and the watery amniotic fluid runs out. 

Put these sentences about the stages of birth in the right order.

7B Pregnancy – Birth

Reproduction

Learning Objectives:

• To describe and explain the fertilisation of an egg in human reproduction.