Where does this come from, and can I check it?

Vessel walls in the brain admit only selected molecules, protecting neural tissue. The figure is taken from NIH, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a human body fact?

Yes. It sits on the Human Body shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Brain capillaries are sealed by tight junctions

Vessel walls in the brain admit only selected molecules, protecting neural tissue Endothelial cells lining brain capillaries are joined so closely that most substances cannot slip between them. Astrocyte end feet wrap the vessels and help maintain the barrier. Small fat-soluble molecules cross freely, while glucose, amino acids and ions need dedicated transporters. It sits in Mondo's human body collection, one of 200 facts that each trace back to the reference below.

Where this comes from

NIH

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Science trivia

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Capillary walls are only one single cell layer thickThin vascular walls enable rapid diffusion of oxygen and metabolic nutrients The amygdala reacts to threats before the cortexA short subcortical pathway reaches it in milliseconds, ahead of conscious appraisal Nearly all sensory signals pass through the thalamusThis paired egg-shaped structure sits at the centre of the brain and routes input onward A thick bundle of fibres links the two hemispheresAround two hundred million axons cross the midline in the corpus callosum Two cortical regions handle speech and comprehensionBroca's area organises speech output while Wernicke's area decodes language meaning The frontal lobe holds plans and restrains impulsesIts forward portion supports foresight, working memory and control over automatic urges

Tags: brain, capillaries, barrier

Brain capillaries are sealed by tight junctions: the short answers

Where does this come from, and can I check it?: Vessel walls in the brain admit only selected molecules, protecting neural tissue. The figure is taken from NIH, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a human body fact?: Yes. It sits on the Human Body shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.