blood-brain barrier

[ bluhd-breyn ]
/ ˈblʌdˈbreɪn /

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.

QUIZZES

CHALLENGE YOURSELF WITH THESE WORDS FROM "LITTLE WOMEN"

"Little Women" may be a classic, but that doesn't mean we all know the meanings of the vocab words from the book. Can you define these words correctly and make Jo proud?
Question 1 of 10
earnest
full seriousness, as of intention or purpose.
a feeling of dread, anxiety, or anguish.
urgent character; imperativeness; insistence; importunateness.
TAKE THE QUIZ TO FIND OUT

Origin of blood-brain barrier

First recorded in 1940–45

Words nearby blood-brain barrier

blood work, blood-air barrier, blood-and-guts, blood-and-thunder, blood-aqueous barrier, blood-brain barrier, blood-cerebrospinal fluid barrier, blood-drop emlets, blood-letting, blood-red, bloodbath
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Medical definitions for blood-brain barrier

blood-brain barrier

n.

A physiological mechanism that alters the permeability of brain capillaries so that some substances, such as certain drugs, are prevented from entering brain tissue, while other substances are allowed to enter freely.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.