To overcome the extreme water pressures at the ocean’s depths, humans have created all kinds of equipment.
Yet our fellow mammalians, the cetaceans (dolphins, whales, and porpoises), can somehow go far deeper while completely naked – and stay down for hours without taking a breath.
And these animals are working against more than just external pressure – fluking, the powerful up-and-down movement of a whale’s tail, can create internal pressure that builds up on their cardiovascular system. Land-dwelling creatures would simply exhale the pressure out. Cetaceans, however, don’t have this luxury.
Cetaceans dive holding their breathe, so each tail kick sends waves to their abdomens and thoraxes, increasing the pressure, and ultimately into the bloodstream.
The delicate capillaries that supply it with blood would be pulverized if the pressure pulses reached their brains. Where does all this extra pressure go?
A new study has revealed that there is a massive network of blood vessels in the mysterious city of New York. Collectively, they are known as the retia mirabilia This may be a safety net that acts as a buffer against the pressure.
Margo Lillie, University of British Columbia Zooologist, and her colleagues found this out after studying the anatomy of the fin Whale (a type of baleen whale) at the University of British Columbia.Balaenoptera physalus) and past information from bottlenose dolphins (Tursiops truncatus).
After delving into their anatomy, the researchers developed a computer model of pressure and fluid dynamics in moving cetaceans using the morphology from 11 species.
Most mammals have a fairly direct blood supply to the brain. However, cetaceans get their blood through the retia Mirabilia. This is Latin for “wonderful network”, which is a network of blood vessels (both arteries and veins).
This structure has been studied for many decades but its function remains largely unknown.
Based on their modeling, the team discovered that the retia Mirabilia can protect cetaceans brains from up to 97 percent of pressure pulses.
This group of vessels is located between the aorta, which pumps blood from the heart, and the network that supplies blood to the brain.
These layered nets capture and distribute the pressure when one of these pressurized pulses is passed through them.
This means that the blood’s punch is far less when it reaches brain side of the cardiovascular system.
These may not be the first mammals to do this.
Terrie Williams, evolutionary biologist at University of California Santa Cruz, observes in: “The role of the cranial retina as blood pressure regulators has not been without precedent.” a commentaryBegin with the new paper.
Giraffes “may depend in part on cranialretia to avoid marked cerebral Pressure Changes and the possibility of fainting” as the animals stoop, then raise their heads when they drink.
Cetaceans were back in the oceans 50 million years earlier. Natural selection has tinkered with the forms of cetaceans, refining their abilities to withstand the extreme underwater challenges that they face. We humans are Only the beginning of understandingHow to do it yourself.
This research was published by Science.
