A Quick Tour around your Brain
How many brain cells does it contain? How heavy is it? How much fat? And how does it work? We take a quick fire science tour round your brain with Naked Scientist Simon Bishop.
Simon - Your brain weighs about 1.5 kg,
Hannah - That's about the same as a bag of sugar or your typical cauliflower - it looks like one too.
Simon - Your brain makes up about 2% of your total body mass
Hannah - Even though it's not that heavy, it's a greedy hungry beast your brain, consuming about 20 % of your daily energy quota
Simon - What's using all this energy? There's almost 100 billion nerve cells up there.
Hannah - that's over 12 x the world population in terms of nerve cells in your head
Simon - These cells use electricity to send signals by pumping charged ions in and out of the cell. They then communicated with other cells by releasing neurotransmitter chemicals -- like dopamine and serotonin
Hannah - Each nerve cell is connected to between 1,000 to 10,000 other nerve cells, and it's through these connections that they send the signals through the brain network.
Simon - So, in total that's almost 1 × 10 to the 14 connections in your brain, or about 100 trillion.
Hannah - The human brain is the fattest organ in the body - over 60% of it is fat.
Simon - This fat wraps itself around the nerve cells and helps to insulate the electrical signal, making communication along nerve cells faster and stronger.
Hannah - Nerve signals can reach up to 120 metres per second, or 300 mph.
Simon - Contrary to popular belief, we don't use only 10% of our brains.
Hannah - It is true that we can only use a few specialised brain circuits at a time, but the rest of the brain is constantly ticking over, ready to be put to work.
Simon - You can find out more about how nerves work in our latest Science Scrapbook, at