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Definition: Blood-brain Barrier |
Blood-brain BarrierNoun1. A mechanism that creates a barrier between brain tissues and circulating blood; serves to protect the central nervous system; "the brain was protected from the large molecules of the virus by the blood-brain barrier". Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. |
| Domain | Definition |
Health | Specialized non-fenestrated tightly-joined endothelial cells (tight junctions) that form a transport barrier for certain substances between the cerebral capillaries and the brain tissue. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
The blood-brain barrier is a physical barrier in the circulatory system that stops many substances from travelling into the brain and central nervous system.
The fact that such a barrier existed was first noticed in experiements by Paul Ehrlich in the late 19th century. Ehrlich was a bacteriologist who was studying staining, used for many studies to make fine structures visible. Some of these dyes, notably the aniline dyes that were then popular, would stain all of the organs of an animal except the brain when injected. At the time Ehrlich attributed this to the brain simply not picking up as much of the dye.
However, in a later experiment in 1913, Edwin Goldmann (one of Ehrlich's students) injected the dye into the spine directly. He found that in this case the brain would become dyed, but the rest of the body remained dye-free. This clearly demonstrated the existence of some sort of barrier between the two sections of the body. At the time it was thought that the blood vessels themselves were responsible for the barrier, as there was no obvious membrane that could be found. It was not until the introduction of the scanning electron microscope to the medical research fields in the 1960s that this could be demonstrated.
In the body, the capillaries (the smallest of the blood vessels) are lined with endothelial cells which contain small gaps between them. This allows chemicals in solution in the body to pass to and from the blood stream, where they can be carried about the body. In the brain these endothelial cells are packed much tighter together, and allow almost nothing to pass in and out. The blood-brain barrier blocks all but the smallest molecules: oxygen, carbon dioxide, and sugars pass with no difficulty, but most drugs are too large to pass the barrier.
The blood-brain barrier appears to exist primarily to protect the brain from the chemical messenger systems flowing around the body. Many bodily functions are controlled via the use of hormones which are detected by receptors on interested cells throughout the body. The hormones are released on cue from the brain, so if they acted on the brain it could cause problems. In addition, the blood-brain barrier is an excellent way to protect the brain from common infection, an infection of the brain is very rare.
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Blood-brain barrier."
Crosswords: Blood-brain Barrier |
| Specialty definitions using "blood-brain barrier": diaziquone ♦ Emepronium ♦ Hexamethonium ♦ Mecamylamine, Moxalactam ♦ nitrosoureas ♦ Tacrine. (references) |
| Domain | Title |
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Source: compiled by the editor from various references; see credits. | |
| Subject | Topic | Quote |
Health | Soon after injection (or inhalation), heroin crosses the blood-brain barrier. (references) | |
Glia make up the blood-brain barrier between blood vessels and the substance of the brain. (references) | ||
But the blood-brain barrier also stymies many efforts to deliver anticancer drugs that may help patients with CNS tumors. (references) | ||
Source: compiled by the editor from ICON Group International, Inc.; see credits. | ||
| Language | Translations for "blood-brain barrier"; alternative meanings/domain in parentheses. | |
Danish | blod-hjerne-barriere. (various references) | |
Dutch | bloed-hersen-barrière. (various references) | |
Finnish | veri-aivo-este. (various references) | |
French | barrière hémato-encéphalique (blood brain barrier). (various references) | |
German | Blut-Hirn-Schranke (blood brain barrier, hemato-encephalic barrier). (various references) | |
Greek | αιματο-εγκεφαλικός φραγμός. (various references) | |
Italian | barriera sangue-cervello, barriera ematoencefalica, barriera ectomesodermica. (various references) | |
Pig Latin | ood-brainblay arrierbay.(various references) | |
Portuguese | barreira hematoencefálica. (various references) | |
Spanish | barrera hematoencefálica (blood brain barrier, hemato-encephalic barrier). (various references) | |
Swedish | blod-hjärnbarriär. (various references) | |
| Source: compiled by the editor from various translation references. | ||
Copyright © Philip M. Parker, INSEAD. Terms of Use.
