What is the importance of the blood-brain barrier?
The blood-brain barrier is a very dense network of tight capillary walls (5 nanometers between cells) that are wrapped around the capillaries of the brain to prevent harmful bacteria, viruses, fungi, and other substances from entering the brain while allowing neurotransmitters and nutrients that nourish the brain to cross. These nutrients include growth factors, water, fat-soluble molecules less than 600 Da, oxygen and carbon dioxide.
