© Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 1 of 31 Biology Human Reproduction
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The menstrual cycle
The menstrual cycle is when the body prepares the uterus lining so that it is able to receive a fertilized egg.
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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
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7B Reproduction
Contents
Ovulation, fertilization and implantation
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Today’s objectives
You should learn about:• What happens during ovulation,
fertilisation and implantation
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Homework
• Worksheet on Atomic structure
• Learn definitions of fertilisation, implantation, fertile period and ovulation
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In males, the sex cells are called sperm. They are made in the testes
Male sex cells
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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
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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
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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.
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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
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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.
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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
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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?
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Contraception
Contraception is the steps we take to reduce the chance of getting pregnant or giving birth
Should contraception be
allowed in Ireland?
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Glossaryegg - The female sex cell.embryo - The first two months of development of a baby.fertilization - When the egg and sperm nuclei fuse.menstruation - The monthly cycle in females.ovary - The part of the female reproductive system that
produces eggs.ovulation - The release of an eggs from the ovary.placenta - The structure made by an embryo to obtain
food and oxygen from its mother.puberty - The time when sex organs begin to work.sperm - The male sex cell.testis - The part of the male reproductive system that
produces sperm.