Scientists have produced 3D looks into shark guts.
A shark 's interior is full of curiosities, starting with rows of laborious teeth that can be replaced with new ones throughout its life. little further down the digestive tract - in fact, just before the shark ends - is another strustrange structure: the spiral intestine, an intricate staircase made of shark flesh.
Scientists have hypothesized that sharks have intestines so complex that they slow down digestion, pulling up the last calorie of their prey. This may even be one of the reasons why sharks can stay long between meals.
But on Wednesday in Proceedings of the Royal Society B , researchers published one of the most detailed looks on these spiral intestines to date by rotating a scanner over them, revealing the complex internal geographies of more than 20 species of sharks. After filling the intestines with fluid, they also made a discovery: some of them work as versionsnatural valve that Nikola Tesla patented in 1920 , drawing the fluid ever further in one direction without moving parts. Video
A cross section of the intestines of a shark. Video by Samantha Leigh.
Samantha Leigh, assistant professor at California State University, Dominguez Hills who led the new study, stated that researchers studying the spiral intestines of sharks often refer to a set of Anatomical Drawings from 1885. Or they can dissect the intestines themselves, marring the structural integrity of the organ at the further examination service. To see the entire structures, she and her colleagues carefully removed the intestines of many species of sharks and imaged them in a CT scanner.
The spiral intestines sharks come in four flavors: a basic spiral, a series of nested funnels pointing in one direction,an interlocking series of funnels pointing the other way, and what's known as a scrolled gut, where the layered sheaths nestle inside each other. In CT scans, the whorls and folds of the structures stand out clearly.
It doesn't matter what a shark ate in regards to the shape of their gut - caphead sharks, which eat both plants and other animals , had volute intestines, as did carnivores hammers . Image Bo Nethead sharks, which eat both plants and 'other animals have a volute intestine. Credit ... Mark Conlin / Alamy
Next, the researchers connected spiral intestines to tubes and observed a mixture of water and glycerol passed through them. They found that indeed, the fluid moved more slowly in the spiral than in a straight section of the intestine of theshark, supporting the idea that spiral intestines help sharks extend their digestion time.
However, they also found that the intestines of the 'funnel had a preferred direction for the flow. The fluid entering at one end flowed much more slowly than the fluid entering the end, implying that inside the animal, the intestine functions as a street to One Way. In mammals, muscle contractions produce this effect . But in sharks, the structure of the gut itself can help.
In fact, the shape of the funnel-shaped gut is reminiscent of curls. of the Tesla valve, a kind of pipe patented by the Serbo-American inventor.
"The purpose of the valve was to produceIt's a flow in one direction without the use of additional mechanical parts or added extra energy, ”said Dr. Leigh. "It looks a lot like how these shark intestines are shaped. Video