Fig. 2.

Cellular structure of the Blood-Brain Barrier (BBB). The endothelial cells (red cells) that compose the brain microvasculature are attached to each other by Tight Junctions that bring these cells close together, limiting the passage of unspecific molecules between them. Pericytes (purple cells) are important regulatory cells that involve the endothelial cells. Finally, the endfeet of astrocytes (yellow/orange cells) also involve this structure, providing regulatory support. The BBB strongly suppresses the entry of unwanted pathogens and cells into the brain parenchyma, protecting the resident cells from insults