Science Interviews


Tue, 15th Oct 2013

A Quick Tour around your Brain

Simon Bishop, Naked Scientist

Listen Now    Download as mp3 from the show Can we make a fake 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



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