The brain — Edexcel GCSE Biology
The cerebral hemispheres, cerebellum and medulla oblongata, how CT and PET scans investigate the brain, and why treating nervous system damage is hard.
Revision notes
3 short notes, in the order of the specification. Each one in short:
The brain is part of the central nervous system, and each region has a different function. The cerebral hemispheres are involved in conscious thought, intelligence, memory and language. The cerebellum coordinates movement and helps to control balance. The medulla oblongata controls unconscious activities, such as heart rate and breathing rate.
Investigating the brain with scans
Higher tierCT and PET scans let doctors investigate the brain without surgery. A CT scan uses X-rays taken from many angles to build up images of the brain's structure, so it can reveal damage or a tumour. A PET scan uses a radioactive tracer, which active areas of the brain use more of, so it shows brain function.
Treating damage to the nervous system is difficult because the brain is complex, delicate and hard to reach inside the skull, and surgery risks damaging healthy tissue. Neurones in the central nervous system do not easily repair themselves, so damage such as a spinal injury can cause permanent paralysis. Some brain tumours cannot be removed safely.
Exam questions
4 exam-style questions (10 marks), each with its mark scheme.
Answer the questionsFlashcards
7 cards: flip them, mark what you knew, and practise the rest.
Practise the cardsMind map
The whole of cells and control on one page, so you can see where this subtopic fits.
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Quick check questions
What does the cerebellum do?
Show answer
It coordinates movement and helps to control balance.
What does the medulla oblongata control?
Show answer
Unconscious activities such as heart rate and breathing rate.
Name one function of the cerebral hemispheres.
Show answer
Any one of: consciousness, intelligence, memory, language.
Which part of the brain would be involved in learning a new language?
Show answer
The cerebral hemispheres.
Frequently asked questions
What are the main parts of the brain and their functions?
The main parts of the brain are the cerebral hemispheres, cerebellum and medulla oblongata. The cerebral hemispheres are involved in conscious thought, intelligence, memory and language. The cerebellum coordinates movement and helps to control balance. The medulla oblongata controls unconscious activities, such as heart rate and breathing rate.
What is the difference between a CT scan and a PET scan?
Higher tier A CT scan uses X-rays taken from many angles to build up images of the brain's structure, so it can reveal damage or a tumour. A PET scan uses a radioactive tracer, which active areas of the brain use more of, so it shows brain function. Both investigate the brain without surgery.
Why is it difficult to treat damage to the nervous system?
Higher tier It is difficult because the brain is complex and delicate, and hard to reach inside the skull, so surgery risks damaging healthy tissue. Neurones in the central nervous system do not easily repair themselves, so damage is often permanent. A spinal injury can cause paralysis, and some brain tumours cannot be removed safely.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026