Question: what is our brain made of

Ed Bracey answered on 6 Nov 2017:

Our brain is made of special cells called neurons. They are special because they’re electrically active – they can switch other neurons on and off. There are 86 billion neurons in a human brain. And each neuron can be connected to as many as 10,000 other neurons. So there are around 50-100 trillion connections in your mind! That’s more stars than there are in the galaxy! That means we’re all walking around with the most complicated things in the known universe inside our skulls.

But the brain is also made of other cells too. They help the neurons out. These support cells (called glial cells) are really important in clearing waste and helping neurons communicate with each other. The glia are also the ones that are most likely to create brain tumours. Because neurons don’t divide that much, they are less likely to form tumours. Glial cells divide quite a lot and are more likely to make tumours. So when you hear of someone having a brain tumour, it’s way more likely to be caused by glial cells than neurons!