Human Brain Facts: Why the Brain Cannot Feel Pain
The adult human brain contains about 86 billion neurons, makes up only about 2% of body mass but uses 20% of the body's oxygen, and cannot feel pain.
How much energy and oxygen does the brain use?
Neurons transmit signals using chemical and electrical impulses. In total they produce about 12–25 watts, enough to light a small light bulb. Although the brain is only about 2% of your body mass, it uses 20% of your oxygen. No other organ comes close, which is why the brain is the first to suffer if the body runs low on oxygen.
Key facts
- The adult brain contains about 86 billion neurons.
- The brain is about 2% of body mass but uses 20% of the body’s oxygen.
Why doesn’t the brain feel pain?
Pain is felt when special nerve fibres called nociceptors send a signal from an injured area to the brain. These fibres are found in the skin, muscles and internal organs, but not in brain tissue itself. That is why some brain surgery can be performed while the patient is conscious.
Where can I read the full story?
This is a short version of “10 Facts about the Human Brain” from OYLA 12+, Vol. 8, Issue 8. The full “10 Facts” spread in OYLA 12+ presents each fact with its own illustration.
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