PSYC 3307 Lecture Notes - Lecture 6: Choroid Plexus, Grey Matter, Nitric Oxide

• School: Carleton University
• Department: Psychology
• Course: PSYC 3307
• Professor: Brian Tansley

Document Summary

Highly-selective, semi-permeable barrier between the circulating arterial blood supply and cns"s interstitial, extracellular fluid. Formed by brain endothelial cells connected by tight junctions . Passive diffusion allows passage of water, 02 and some other gases and lipid-soluble molecules. Active transport of glucose and amino acids. Permits selective transport of substances from the arterial supply into the parenchyma. Ions cross via active pumps (i. e. , pumps that use energy) Most nutriments cross the bbb via facilitated diffusion (e. g. , by coupling nutriment to ions that move down a concentration gradient) No csf brain barrier; therefore there must be a blood-csf barrier (formed by the epithelium of the choroid plexus) Hint: highly lipophilic substances directly cross the membrane, therefore one would expect that increasing a molecule"s lipophilicity would increase its efficiency in crossing the bbb. Blood brain permittivity is based on surface activity, molecular properties of hydrophobic and charged residues