Inhalation Explanation

Breathing – it happens automatically, keeps you alive, and no doubt you rarely think about it. But scientists do – they’re the pondering type – and that’s why they’ve figured out the answer to a niggling question about breathing control. They knew that sensors in the brain’s breathing centre – the retrotrapezoid nucleus (RN) – detect rising carbon dioxide (CO₂) levels in the blood and trigger the lungs to inflate. They also knew that high CO₂ causes acidity, which can damage tissues, especially the brain. Here was the niggle: to protect itself, the brain dilates its blood vessels to increase flow and wash out CO₂, but in the RN this would be counterproductive, reducing the signal to breath. So, what happens there? It turns out that, unlike other blood vessels in the brain, those in the RN constrict in response to CO₂, increasing the molecule’s concentration, ensuring its detection, and thus prompting a timely inhalation.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image by Dan Mulkey, University of Connecticut
• Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA and Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
• Image copyright held by original authors
• Research published in eLife, April 2017