blood-brain barrier

[ bluhd-breyn ]

/ ˈblʌdˈbreɪn /

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noun Physiology.

a layer of tightly packed cells that make up the walls of brain capillaries and prevent substances in the blood from diffusing freely into the brain: passage across the cell membranes is determined by solubility in the lipid bilayer or recognition by a transport molecule.

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Origin of blood-brain barrier

First recorded in 1940–45

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use blood-brain barrier in a sentence

I was out, maybe in the Great Barrier Reef catching black marlin.
The Story Behind Lee Marvin’s Liberty Valance Smile|Robert Ward|January 3, 2015|DAILY BEAST
Like other barrier-breakers before him, Colfer suffered his share of doubters.
Chris Colfer on Writing, Acting, and the Pain of Being A Pop Culture Trailblazer|Oliver Jones|December 15, 2014|DAILY BEAST
Language was no barrier; just about every tongue on the planet was babbling away, caught up in the elaborate mystique of a cult.
Sherlock Holmes Vs. Jack the Ripper|Clive Irving|November 16, 2014|DAILY BEAST
It was called, rather dramatically, breaking the sound barrier.
Virgin Galactic’s Flight Path to Disaster: A Clash of High Risk and Hyperbole|Clive Irving|November 1, 2014|DAILY BEAST

He saw a chain barrier covered with PVC piping that the Jeep had apparently struck and damaged before becoming stuck.
Manhunt for a Cop-Hating Pennsylvania ‘Survivalist’|Michael Daly|September 17, 2014|DAILY BEAST
He was fired at by the sepoys, of course, but horse and man escaped untouched and the low barrier was leaped without effort.
The Red Year|Louis Tracy
But scorn is far more volcanic than glacial and a poor barrier between sex and judgment.
Ancestors|Gertrude Atherton
The barrier between them lowered perceptibly again, and Tom felt a momentary return of the confidence he had lost.
The Wave|Algernon Blackwood
The talk between them rarely touched reality, as though a barrier deadened their very voices.
The Wave|Algernon Blackwood
Guilelessly, the old man, in a few words, had swept away the barrier Mary and I had raised between us.
The Soldier of the Valley|Nelson Lloyd

Scientific definitions for blood-brain barrier

blood-brain barrier

A physiological mechanism that alters the permeability of capillaries in the brain, so that some substances, such as certain drugs, are prevented from entering brain tissue, while other substances are allowed to enter freely.

Cultural definitions for blood-brain barrier

blood-brain barrier

The separation of the brain, which is bathed in a clear cerebrospinal fluid, from the bloodstream. The cells near the capillary beds external to the brain selectively filter the molecules that are allowed to enter the brain, creating a more stable, nearly pathogen-free environment.

notes for blood-brain barrier

Oxygen, glucose, and white blood cells are molecules that are able to pass through this barrier. Red blood cells cannot.