Meet Your Brain
Three pounds of tissue that can imagine galaxies and remember your childhood — let's get acquainted.
Inside your head sits about 1.4 kilograms of soft, folded tissue made of roughly 86 billion neurons. It makes up only about 2% of your body weight, yet it burns around 20% of your energy. Thinking is genuinely hungry work — the constant electrical and chemical activity is metabolically expensive.
Your brain never switches off. Even while you sleep it is sorting memories, clearing waste, repairing itself, and quietly keeping your heart beating and lungs breathing. Across this course we move from the whole organ down to one neuron and back up to mind-level questions — but the through-line is that the brain is a living, changeable system, not a static circuit board.
- The brain is ~2% of body weight but uses ~20% of your energy.
- It contains about 86 billion neurons forming trillions of connections.
- It is never fully off — it runs your body and consolidates memory during sleep.
- It is not fixed: it rewires itself based on what you do.
Try the full interactive course — free
Read the lessons here, or take the same course as interactive, gamified lessons in the app. Free account, your progress saved.
Start the interactive course →Free educational content. Manasaya is a learning platform, not a medical or clinical service.