Control center
About 2% of body weight, yet it uses roughly 20% of the body's resting energy — mostly from glucose.
The cerebrum handles thought and voluntary movement, the cerebellum coordinates balance and fine movement, and the brainstem runs breathing and heart rate.
The brain relies mainly on glucose. During prolonged fasting or very low carbohydrate intake it can use ketones for part of its energy.
The blood–brain barrier tightly controls which molecules pass from blood into brain tissue.
This atlas explains how the brain works. Sudden severe headache, weakness on one side, confusion or trouble speaking needs emergency care.
General education only, not medical advice. Drafted Oct 2026 · pending qualified expert review.