Nervous system
Brain
The brain is the control centre of the body. It governs thought, memory, emotion, movement, the senses and vital automatic functions like breathing — through billions of nerve cells communicating constantly.
What it is
The brain is a soft, complex organ of billions of nerve cells (neurons), protected inside the skull. With the spinal cord it forms the central nervous system.
Where it is
Inside the skull, cushioned by fluid and protected by the bones of the cranium.
What it does
Controls virtually everything: conscious thought, memory, emotion, language, the senses, voluntary movement, and automatic functions such as heartbeat, breathing and temperature.
How it works
Networks of neurons pass electrical and chemical signals to one another. Different regions specialise — for example movement, vision, language and balance — but work together. The brain constantly receives information from the senses and sends instructions to the body.
When things go wrong
Common conditions affecting the brain
- Stroke
- Dementia (including Alzheimer's disease)
- Epilepsy
- Migraine
- Brain injury
Education and reference only. This explains the anatomy in plain terms and is not a diagnosis. Sudden severe symptoms — such as severe chest pain, breathlessness or collapse — are an emergency; call 999.
Looking after it
Keeping your brain healthy
Protecting the heart and blood vessels (which supply the brain), staying mentally and physically active, sleeping well, not smoking, and protecting the head from injury all support brain health.
Did you know?
An interesting fact
The brain uses around 20% of the body's energy despite making up only about 2% of body weight.
Answers
Brain: frequently asked questions
What does the brain do?
The brain is the body's control centre, governing thought, memory, emotion, the senses, movement and vital automatic functions like breathing and heartbeat.
What are the signs of a stroke?
Use FAST: Face drooping, Arm weakness, Speech difficulty, Time to call 999. A stroke is an emergency — fast treatment saves brain tissue.
The nervous system
Related organs
Sources
Where this is drawn from
- NHS — Anatomy and body systems
- Gray's Anatomy for Students
- TeachMeAnatomy / TeachMePhysiology
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