Circulatory systems — Cambridge IGCSE Combined Science

The circulatory system: blood vessels with a pump (the heart) and valves that keep the blood flowing in one direction.

Spec B9.1Transport in animals, subtopic 1 of 4

Revision notes

1 short note, in the order of the specification. Each one in short:

The circulatory system
Fish have a single circulation, passing through the heart once; mammals have a double circulation, with separate pulmonary and systemic circuits.

2 exam-style questions (3 marks), each with its mark scheme.

1 card: flip them, mark what you knew, and practise the rest.

The whole of transport in animals on one page, so you can see where this subtopic fits.

Free PDFs to print or save.

What is the circulatory system?
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A system of blood vessels with a pump and valves to ensure one-way flow of blood.
What is the pump of the circulatory system?
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The heart.
What is the job of the valves in the circulatory system?
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To stop blood flowing backwards, so it flows one way only.

Written and checked against the Cambridge IGCSE Combined Science (0653) specification · Updated October 2026