It looks like you are using an older version of Internet Explorer which is not supported. We advise that you update your browser to the latest version of Microsoft Edge, or consider using other browsers such as Chrome, Firefox or Safari.

Blood-brain barrier

If you think about this one too long it might start to tickle: your brain wears a raincoat. JK. There’s no rain coat, there’s actually a layer of endothelial cells around the blood vessels in your brain (and spinal cord), that work to keep viruses and other harmful substances out of your bloodstream. But isn’t a brain in a rain coat more fun to think about?