Human reproduction Cambridge IGCSE Co-ordinated Sciences (9–1) revision
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In plain words
A new human starts when one sperm cell joins one egg cell. The single cell that results divides again and again, settles into the lining of the uterus, and over nine months grows into a baby, fed and supplied with oxygen by its mother through the placenta.
Three things to know
- Male: the testes make sperm, which travel along the sperm ducts, are mixed with fluid from the prostate gland, and leave through the urethra in the penis. Female: the ovaries release eggs, which travel down the oviducts to the uterus; the cervix is its neck and the vagina leads outside.
- Fertilisation, the fusion of the sperm and egg nuclei, happens in the oviduct. The zygote divides into a ball of cells (an embryo), which implants in the lining of the uterus.
- The placenta lets dissolved food and oxygen pass from the mother's blood to the fetus, and carbon dioxide and urea pass back. The umbilical cord joins the fetus to the placenta. The amniotic fluid cushions the fetus.
Tips and tricks
- The mother's blood and the baby's blood never mix. Substances diffuse across the placenta.
- Sperm are adapted to swim (a tail, many mitochondria). An egg is adapted to feed the early embryo (a store of food in its cytoplasm).
It lands in your notebook with its questions as flashcards.
Human reproduction: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Where are sperm made?
The testes also make testosterone.
Where does fertilisation usually happen?
The egg is met by sperm on its way to the uterus.
What is the function of the placenta?
Oxygen and food go one way, wastes the other.
What joins the fetus to the placenta?
It contains blood vessels of the fetus.
What does the amniotic fluid do?
The fetus floats in it.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 7 marks. Write your answers on paper, then check them.
Human reproduction
Cambridge IGCSE Co-ordinated Sciences (9–1) 0973 · 7 marks · papermunch.org
Name ______________________________ Date ______________
State where fertilisation and implantation take place.[2]
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Fertilisation in the oviduct; implantation in the lining of the uterus.
Describe the function of the placenta.[3]
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It allows the exchange of substances between the mother's blood and the fetus's blood: oxygen and dissolved nutrients pass to the fetus, and carbon dioxide and urea pass to the mother.
State the function of the amniotic fluid.[2]
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It surrounds, supports and cushions the fetus, protecting it from knocks.
Answers: Human reproduction
- 1. Fertilisation in the oviduct; implantation in the lining of the uterus.
- 2. It allows the exchange of substances between the mother's blood and the fetus's blood: oxygen and dissolved nutrients pass to the fetus, and carbon dioxide and urea pass to the mother.
- 3. It surrounds, supports and cushions the fetus, protecting it from knocks.