blood–brain barrier

https://doi.org/10.1351/goldbook.11640
Selectively permeable structure that restricts the exit of blood cells and many substances from the brain capillaries into the extracellular space of the brain.
Note: It consists of a layer of tightly packed cells (chiefly endothelial cells and astrocytes) and basement membrane, continuous along the brain capillaries.
Source:
PAC, 2015, 87, 841. (IUPAC Glossary of terms used in neurotoxicology (IUPAC Recommendations 2015)) on page 853 [Terms] [Paper]