If you look at some parts of the circulatory systems of whales and dolphins, you might think you’re looking at a Jackson Pollock painting rather than blood vessels. These cetaceans have a particularly dense, complex network of blood vessels, mostly associated with the brain and spine, but scientists don’t know why. A new analysis shows that, Cyber protects cetacean brains The blood pressure pulses the animals endured while diving deep, researchers reported on Sept. 23. science.
Whales and dolphins “have undergone these very amazing vascular adaptations to support their brains,” said Ashley Blawas, a marine scientist at Duke University Marine Laboratory in Beaufort, North Carolina, who was not involved in the study.
This vascular network is called retia mirabilia, which means “wonderful web,” and is present in some other animals besides cetaceans, including giraffes and horses. But these networks were not found in other aquatic vertebrates, unlike whales, such as seals. Scientists therefore suspect that the bizarre retinas of cetaceans play a role in keeping blood pressure in check.
When whales and dolphins dive, they move their tails up and down in an undulating pattern, which increases blood pressure. Land animals that experience similar surges, such as galloping horses, are able to release some of their stress by exhaling.But some cetaceans hold their breath long dive (SN: 9/23/20). If there is no way to relieve this pressure, these blasts can tear blood vessels and damage other organs, including the brain.
In the new study, Margo Lillie, a biomechanics researcher at the University of British Columbia in Vancouver, and colleagues used morphological data from 11 cetacean species to create a computational model that mimics the animal’s bizarre retina. It revealed that the arteries and veins in this clump of blood vessels are very close together and may sometimes even be connected. The singular retina thus balances the blood pressure differences created by diving, perhaps by redistributing blood pulses from arteries to veins and vice versa. In this way, the network can eliminate or at least attenuate huge blood pressure fluctuations that might otherwise reach and damage the brain.
network “makes [blood flow] In a way, you never lose blood in a vein, it doesn’t collapse on its own, and you don’t have arterial blood going quickly into the brain,” said Tiffany Keenan, a marine biologist at American University in North Carolina, N.C., who was not involved in the study. “It’s great to know what we’ve always wanted to know, but no one has been able to show. “
Studying cetaceans remains tricky because of their conservation status and limited access to samples, often from stranded animals, the researchers said. For this reason, one limitation of the new study is that the researchers must input data from different species to make their models.
“They take a little bit from here and a little bit from there and mix dolphins, belugas and beaked whales — it’s kind of like a quilt,” said Andreas Fahlman, a marine scientist at the Oceanogràfic Foundation in Valencia, Spain, who was not involved in the study. .
As a result, the model may miss important aspects that may be specific to other species that have unique anatomy and even move differently, some closer to the surface and some deeper. A closer look at the circulatory systems of whales and dolphins, perhaps using non-invasive techniques such as sensors that can measure blood flow and pressure, may help confirm that computational models reflect real-life dynamics.