How whales protect their brains

by time news

Dhe blood pressure is a complex matter: it is always higher in the veins that lead to the organs than in the veins that carry blood back to the heart. In animals that move with very powerful whole-body swings, these strong movements can also increase blood pressure – which could lead to dangerous pressure peaks in the fine capillaries in the brain, for example.

Scientists have been puzzling for years how it is possible that the theoretically assumed pressure peaks in the brain and other sensitive organs do not lead to tearing or bursting of the arteries. But evolution solved this problem in an elegant way: through the formation of a special type of blood vessel, as a study in the journal Science now shows.

Protective “miracle net”

The so-called miraculous net is known from the kidneys of mammals – an extremely sensitive organ with a very high blood supply, which requires a large surface of the blood vessels for the most far-reaching detoxification of the blood. This “Rete mirabile” describes a very strong fanning out of the arteries. Figuratively speaking, the blood vessels fan out from the thickness of a garden hose to tiny fine capillaries – and then unite again to form the garden hose. On the one hand, this fanning out leads to an increase in surface area (important in the kidneys as a detoxification organ), but it also causes the pressure in the individual vessels to drop.

According to researchers led by Margo Lillie, who until recently did research at the University of British Columbia in Vancouver, that seems to be the whale’s secret. Before the blood reaches her brain, it is transported through such a “miracle net”. The pressure that mammals generate in the blood vessel system with their powerful body waves cannot harm their brain.


In various tissues, arteries fan out into a rete mirabile (miracle net).
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Image: Wayne Vogl

Without the rete mirabile, toothed whales could therefore hardly reach the speed with which they pursue their prey unscathed. And the world would probably be poorer by the spectacular jumps with which the animals seem to catapult themselves out of the waves with great enthusiasm.

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