Blood-Brain Barrier Overview: Structural and Functional Correlation

Figure 5

A schematic diagram of the endothelial cells that form the BBB and their associations with the perivascular end feet of astrocytes showing pathways across the BBB. (a) Generally, tight junctions prevent water-soluble chemicals from penetrating. (b) On the other hand, the enormous surface area of the endothelium’s lipid membranes provides an excellent diffusive pathway for lipid-soluble substances. (c) Transporter proteins for glucose, amino acids, purine bases, nucleosides, choline, and other chemicals are found in the endothelium. (d) Specific receptor-mediated endocytosis and transcytosis pick up drugs and particular proteins, such as insulin and transferrin. (e) Adsorptive-mediated transcytosis for transport macromolecules and charged agents to brain. (f) Cell mediated transcytosis pathway depends on leukocytes to pass the BBB. (created by author according to information from [67]; BioRender).