Brain Facts



  • The human brain is made up of over 100 billion nerve cells called neurons.
  • Each neuron is connected to as many as 25,000 other neurons — so the brain has trillions and trillions of different pathways for nerve signals.
  • Girls’ brains weigh 2.5% of their body weight, on average, while boys’ brains weigh 2%.
  • About 0.85 litres of blood shoots through your brain every minute. The brain may be as little as 2% of your body weight, but it demands 12 — 15% of your blood supply.
  • An elephant’s brain weighs four times as much as the human brain. Some apes, monkeys and dolphins are quite near our brain—body ratio.
  • The cerebral cortex is the outside of the brain. If laid out flat, it would cover a bed.
  • The left hemisphere (half) of the upper part of the brain is more dominant in speech, writing and general language, the right half in pictures and ideas.
  • Conscious thoughts and actions happen in the cerebral cortex.
  • A human brain has a cerebral cortex four times as big as a chimpanzee, about 20 times as big as a monkey’s, and about 300 times as big as a rat’s.
  • Unconscious, automatic activities like breathing, hunger and sleep are controlled by structures such as the brain stem and the hypothalamus.
  • Some scientists claim that we humans are the only living things that are self conscious, meaning that we alone are actually aware that we are thinking.
  • No one knows how consciousness works – it is one of science’s last great mysteries.
  • Most of your thoughts seem to take place in the cerebrum (at the top of your brain), and different kinds of thought are linked to different areas, called association areas.
  • Each half of the cerebrum has four rounded ends called lobes – two at the front, called frontal and temporal lobes, and two at the back, called occipital and parietal lobes.
  • The frontal lobe is linked to your personality and it is where you have your bright ideas.
  • The temporal lobe enables you to hear and understand what people are saying to you.
  • The occipital lobe is where you work out what your eyes see.
  • The left half of the brain (left hemisphere) controls the right side of the body. The right half (right hemisphere) controls the left side. tile half of the brain is always dominant (in charge). Usually, the left brain is dominant, which is why 90% of people are right-handed. Ihe parietal lobe is where you register touch, heat and cold, and pain.