Asked by: Philip Boylan, by email

The blood-brain barrier (BBB) exists to protect the brain from infection and to isolate it from hormones and neurotransmitters used in the rest of the body. It prevents bacteria and large molecules from reaching brain cells, but it is by no means a complete barricade. Oxygen, CO2, water and glucose are all able to pass through the BBB. Fat-soluble drugs, like barbiturates, are also able to cross it.

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Authors

luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

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