The average human brain weighs about 1,400 g (3 lbs) It’s 14 cm wide, 16.7 cm long and 9.3 cm high It’s about 78% water (compared to about 70% for the whole body) 60% of your brain’s dry weight is fat, making it your fattiest organ It’s made up of 86 billion neurons, or brain cells, forming over 100 trillion connections, as well as about a trillion glia, or support cells A piece of brain tissue the size of a grain of sand contains 100,000 neurons and 1 billion synapses all communicating with each other Neurons have 3 parts, the soma or body, the dendrites, and the axon, which reaches out towards other cells The longest axon in the human body is about 1 m long, stretching from the base of the spine, to the big toe The speed of a nerve impulse to your muscles is up to 120 m/s.

Pain signals are slower, travelling between 0.5-30 m/s While your brain makes up about 2% of your body mass, it uses about 20% of your daily oxygen and calorie needs It produces about 500 ml of cerebrospinal fluid per day, but reabsorbs it so that only 100 to 160 ml surround the brain at any given time And it generates between 10-23 watts of power–or enough energy to power a light bulb All of these numbers add up to one brain, belonging to one person who is, in a lot of ways, immeasurable Your brain makes you, you.