BLOOD-BRAIN BARRIER Definition & Meaning

blood-brain barrier

[ bluhd-breyn ]

Phonetic (Standard)IPA

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.

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.

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.

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Notes

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

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�y��vlog History and Origins

Origin of blood-brain barrier¹

First recorded in 1940–45

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Example Sentences

Examples have not been reviewed.

The authors of the lesions study note that experts are still uncertain whether these tiny plastic particles cross the blood-brain barrier or the gut-brain axis.

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The previous study showed that glyphosate crosses the blood-brain barrier, a protective layer that typically prevents potentially harmful substances from entering the brain.

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They said the new filing didn’t back the company’s claims that the product would be absorbed into the bloodstream at low levels and that it wouldn’t cross the blood-brain barrier.

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The blood-brain barrier is a natural protective shield that prevents harmful substances from entering the brain.

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This approach allows for the use of low doses of potent drugs while bypassing the blood-brain barrier.

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