Blood–brain barrier

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Part of a network of capillaries supplying brain cells
A cortical microvessel stained for blood–brain barrier protein ZO-1

The blood–brain barrier (BBB) is a highly selective permeability barrier. It separates the circulating blood from the brain extracellular fluid in the central nervous system (CNS).

The blood-brain barrier is formed by capillary endothelial cells.[1] It allows the passage of water, some gases, and lipid-soluble molecules by passive diffusion. It also allows the selective transport of molecules such as glucose and amino acids which are crucial to nerve function.[2]

On the other hand, the blood-brain barrier may prevent the entry of lipophilic potential neurotoxins by means of an active transport mechanism.

A few small regions in the brain do not have a blood-brain barrier.

References[change | change source]

  1. de Vries, Helga E. et al (1997). "The blood-brain barrier in neuroinflammatory diseases". Pharmacological Reviews 49 (2): 143–156. PMID 9228664 .
  2. "About". Blood brain barrier. Johns Hopkins University. Retrieved 7 May 2013.