Fertilisation. The male reproductive system The female reproductive system.

Fertilisation

The male reproductive system

The female reproductive system

Male or female?

Reproductive system

Label the parts….

Label the parts

From a cell to DNA

In males, the sex cells are called sperm.

Sperm are produced in sex organs called testes.

Sex cells – sperm

In females, the sex cells are called eggs.

Eggs are produced in sex organs called ovaries.

Sex cells – egg

An egg is so big that this is how small a sperm looks next to it.

nucleus containing chromosomes

jelly coat

cytoplasm

membrane

Fertilization and cell division – animation

Identical twins – animation

Non-identical twins – animation

Sexual ReproductionAlthough all cells carry the genetic code, special cells are produced for sexual reproduction – they are called gametes.In animals, these are the eggs and sperm.In plants, they are the eggs and pollen.Gametes are different from all other cells because they only carry one copy of each chromosome.For example, human gametes (sperms and eggs) have only 23 chromosomes, not 46 like all other body cells.

The process of a male and female gamete combining is called fertilisation.The fertilised egg is called a zygote and is the very first cell of a new individual. A zygote will have the normal number of chromosomes – one half from the male gamete, another half from the female gamete.This whole process is called sexual reproduction.

The menstrual cycle

The menstrual cycleThe menstrual cycle is when the body prepares the uterus lining so that it is able to receive a fertilized egg.

The fertile period

• This is the time in the cycle when the woman could get pregnant after having sex.

Between days 11 and days 16 of the menstrual cycle

Label the parts…

In males, the sex cells are called sperm. They are made in the testes

Male sex cells

In females, the sex cells are called eggs. They are made in the ovary.

Female sex cells

An egg is so big that this is how small a sperm looks next to it.

nucleus containing chromosomes

Sperm or egg?

In the female, one of the ovaries releases an egg every 28 days. This is called ovulation.

During sexual intercourse millions of sperm are ejaculated into the vagina.

If a sperm meets the egg a zygote is formed. This called fertilization.

Ovulation and fertilization

Fertilization and implantation

What happens after fertilisation?

• Once the zygote is made the cells divide many times

• It is now called an embryo and it will sink into the lining of the uterus, this is called implantation.

A placenta is formed which allows it to exchange material with the mother

The umbilical cord joins the embryo to the placenta.

How does an embryo get food andoxygen and how does it get rid of waste?

The placenta

The placenta

What happens in the placenta?

• In the placenta, food and diffuse from the mother’s blood into the blood of the fetus.

• Carbon dioxide and waste products diffuse from the blood of the fetus to the mother’s blood.

After the first eight weeks of pregnancy,a human embryo is then called a fetus.

The fetus continues to develop and grow inside its mothers’ uterus for a total of 40 weeks.

What happens next?

From embryo to fetus

From embryo to fetus – animation

Birth animation

Puberty is the stage between the ages of 10 – 18 when the sex organs of humans become active

Think about…

What happens to i) boys and ii) girls during puberty?

What is puberty?

Puberty in girls

Puberty in boys

Multiple-choice quiz