blood-brain barrier

[ bluhd-breyn ]

noun

, Physiology.

1. 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

1. 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

1. 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

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

Word History and Origins

Origin of blood-brain barrier¹

First recorded in 1940–45

Example Sentences

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

From Science Daily

The new diglyceride is predicted to cause a higher concentration of omega-3 molecules to rapidly penetrate the blood-brain barrier.

From Science Daily

"This means that this drug can actually cross the blood-brain barrier to attack the tumor in the brain," Zhang said.

From Science Daily

It is thought that pollution could negatively affect mental health via numerous pathways, including by compromising the blood-brain barrier, promoting neuroinflammation and oxidative stress, and directly entering the brain and damaging tissue.

From Science Daily

Potential therapies often can’t traverse the blood-brain barrier, the protective layer that shields the organ.

From Science Magazine