blood-brain barrier: meaning, definition, pronunciation and examples
Low (specialized term)Formal/Technical (primarily medical, biological, neuroscientific contexts)
Quick answer
What does “blood-brain barrier” mean?
A highly selective semipermeable membrane that separates the circulating blood from the brain's extracellular fluid, protecting the central nervous system from potentially harmful substances.
Audio
Pronunciation
Definition
Meaning and Definition
A highly selective semipermeable membrane that separates the circulating blood from the brain's extracellular fluid, protecting the central nervous system from potentially harmful substances.
A metaphorical barrier that prevents certain ideas, information, or influences from entering one's consciousness or understanding.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage; spelling and pronunciation are consistent.
Connotations
Identical technical connotations in both varieties; metaphorical use is equally rare.
Frequency
Equally low frequency in both varieties, confined to specialized fields.
Grammar
How to Use “blood-brain barrier” in a Sentence
The drug can/cannot cross the blood-brain barrier.Disease X affects the integrity of the blood-brain barrier.Researchers are studying ways to penetrate the blood-brain barrier.Vocabulary
Collocations
Usage
Meaning in Context
Business
Rare; potentially used metaphorically in consultancy to describe resistance to new strategies ('We need to overcome the management's blood-brain barrier to innovation').
Academic
Common in neuroscience, pharmacology, physiology, and medicine papers discussing drug delivery or neuroprotection.
Everyday
Virtually never used in casual conversation.
Technical
Core terminology in neurology, describing a critical physiological structure.
Vocabulary
Synonyms of “blood-brain barrier”
Neutral
Weak
Vocabulary
Antonyms of “blood-brain barrier”
Watch out
Common Mistakes When Using “blood-brain barrier”
- Misspelling as 'blood-brain-barrier' (over-hyphenation).
- Using it as a countable noun (*'two blood-brain barriers').
- Incorrect preposition: *'pass through the blood-brain barrier' is less idiomatic than 'cross'.
FAQ
Frequently Asked Questions
No, it's not a single wall. It's a complex system of specialised endothelial cells lining brain capillaries, supported by astrocytes and pericytes, that tightly control what passes from the blood into the brain tissue.
Yes, small lipid-soluble molecules (like oxygen, carbon dioxide, alcohol), water (via special channels), and essential nutrients (like glucose and amino acids) cross via specific transport mechanisms. Most large molecules and pathogens are blocked.
Over 98% of small-molecule drugs and nearly 100% of large-molecule drugs cannot cross the barrier. Developing treatments for brain diseases often requires designing drugs that can penetrate it or finding ways to temporarily open it.
Very rarely. It might be used metaphorically in psychology or communication studies to describe a person's mental resistance to new or challenging ideas, but this usage is not standard.
A highly selective semipermeable membrane that separates the circulating blood from the brain's extracellular fluid, protecting the central nervous system from potentially harmful substances.
Blood-brain barrier is usually formal/technical (primarily medical, biological, neuroscientific contexts) in register.
Blood-brain barrier: in British English it is pronounced /ˌblʌd breɪn ˈbæriə/, and in American English it is pronounced /ˌblʌd breɪn ˈbæriər/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of a security checkpoint (BARRIER) at the entrance to a VIP area (the BRAIN), checking IDs of everything in the BLOOD supply.
Conceptual Metaphor
PROTECTIVE FILTER / GATEKEEPER (The brain is a fortress; the barrier is the gate.)
Practice
Quiz
What is the primary function of the blood-brain barrier?