Meet the homunculus
Your brain has different sensory areas, dedicated to receiving sensory input from various parts of your body. But not all areas are equally sensitive…
The picture to the left is the so-called ‘sensory homunculus’. It is a representation of the human body where each body part is scaled according to how much brain area is dedicated to processing its inputs. So areas which appear enlarged (like the hands) have large regions of the cortex dedicated to them. Others, like the ankle, are less important from the brain’s point of view.
In short, this is how your brain sees you!
The brain is suspended in Cerebrospinal fluid, effectively floating in liquid that acts as both a cushion to physical impact and a barrier to infections.
Weight, Size and Power
When comparing the brains of different animals, brain size tends to vary according to body size. The largest brains are those of sperm whales, weighing about 8 kg. An elephant’s brain weighs just over 5 kg, a bottlenose dolphin’s 1.5 to 1.7 kg, whereas a human brain is around 1.3 to 1.5 kg. The largest brain-to-body mass ratio is thought to be found in the shrew. Incredibly, although the human brain makes up just 2% of the body’s weight, it uses around 20% of its energy. While awake, it generates between 10- 23 watts of power–enough energy to power a light bulb.
The human brain is made up of over 100 billion nerve cells (about the same number of trees make up the Amazon rainforest) and each cell is connected to around 10,000 other cells. This means the total number of connections in the human brain, is equal to the number of leaves that can be found in the rainforest- approximately 1000 trillion!
Your brain (a whistle stop tour)!
As you would expect different areas of the brain carry out different functions. These were first discovered by the ancient Egyptians and Greeks in 400 BC and it was Hippocrates who realised that the brain played an important role in sensation and intelligence.
The frontal lobe (region behind the forehead) is heavily involved in planning, problems solving and decision making. This area allows us to regulate our primate responses and produce socially appropriate behaviour, making us distinct from other mammals. The temporal lobe (found behind the temples) is involved in language processing and is where long term memories are stored. Conversely the area of the brain at the very back of the head (occipital lobe) is dedicated almost exclusively to vision and helps to create the colourful 3D world that we see. Finally the area just behind the ears (parietal lobe) integrates information across the senses, mapping objects in our environment and helping with hand eye co-ordination.
Tom- ‘I used to be a girl’!?
Everyone’s brain starts out as a female! The brain of a male doesn’t become masculinized until around eight weeks after conception- by the hormone testosterone!
Send us your own fun brain facts and we will include the best ones on this site!