Blood Brain Barrier Essay -- Biology

The brain is permeated by a vast network of tiny blood vessels called capillaries- so tiny and thin that blood cells have to pass through in single file. In the brain alone there are enough capillaries that if you laid them all out end to end they would stretch from Tucson to Tijuana. These capillaries are surrounded by a single layer of cells. That layer of cells forms a barrier between the capillaries and the cells and fluid of the brain. These barrier-forming cells are called "endothelial cells". You can think of "endothelial" as a synonym for "lining" or even just "barrier". When we use the phrase Blood Brain Barrier, (which for obvious reasons we'll refer to as BBB from here on out!), we're talking about all of these endothelial ("barrier") cells collectively. Function of the BBB The cell membranes of the BBB contain transport proteins. If the brain is a nightclub, the transport proteins are bouncers. They decide who gets in, and who gets kicked out. On this website we'll be introducing you to the most important transport proteins- OATP, MDR1, and MDR2. Don't let all the acronyms intimidate you- read carefully and you'll be fine. If the nightclub/bouncer analogy doesn't work for you, you could also think of them as little vacuum pumps and blowers. An extremely detailed view of their actual mechanisms is beyond current knowledge. Importance of the BBB Without the BBB, undesirable molecules could freely diffuse from the capillaries to the fluid that surrounds the brain cells. These undesirable molecules include: TOXINS- poisons taken in from the environment. IONS- that might upset the delicate electrochemical gradients of the cerebral fluid. ACIDS and BASES- that might upset the cerebral ... ...aks down the BBB, so the mice infected with GBS lacking this toxin developed less bacterial meningitis than those infected with the normal GBS. -Doran says: Ââ€Å"These findings demonstrate a novel function of the blood-brain barrier, to act as a sentry that detects the threat of a bacterial pathogen and responds by triggering an immune response to clear the infection. 3. Neuwalt- Researches treatment of brain tumors with chemotherapy, hard because of the BBB (natural defense against chemical transport into the brain) introduction of chemicals to the brain by shrinking endothelial cells that make up the BBB with a concentrated sugar solution that creates gaps in the BBB allowing chemicals to enter (called Blood-Brain Barrier Disruption Therapy) project tenfold to a hundredfold more successful than normal chemotherapy and intra-arterial chemotherapy (Neuwalt, 1998)