Tag: blood vessels

How Owls Rotate Their Heads So Far Without Snapping Their Necks

By Breanna Draxler | February 1, 2013 12:22 pm

A baby barn owl demonstrates the natural neck flexibility of the owl. Researchers studied snowy, barred, and great horned owls. Image courtesy of marilyn barbone / shutterstock.

Most animals, humans included, can only turn their heads so far without snapping their necks or causing a stroke. But owls can rotate their necks 270 degrees—an impressive ¾ of a full rotation—without causing any harm. Owls have unmoving eyeballs, so neck rotation is necessary for the animal to have any sort of peripheral vision. How can owls pull it off without cutting off the blood supply to their brains?

For the first time, researchers at Johns Hopkins think they may have an explanation. By dissecting dead owls, the researchers pinpointed adaptations in the vertebrae and blood vessels that they think allow the owl to achieve such a feat. Their illustrated results were published in Science today, and won first prize for posters in the NSF/Science visualization challenge.

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CATEGORIZED UNDER: Living World, Top Posts

Gross But Cool: Weaving Blood Vessels with Threads of Human Tissue

By Veronique Greenwood | May 7, 2012 1:14 pm

vessels
This machine is weaving 48 strands of human connective tissue together into a tube.

Growing fresh blood vessels is a much fantasized-about goal of biomedical engineers. It sounds vaguely vampiric, but the idea is to replace the veins in the arms of dialysis patients, which are a mess from being breached several times a week to be hooked up to a blood-cleaning machine. From there, engineers hope to provide off-the-shelf replacements for heart valves and such.

Most approaches involve getting human cells—either donor cells or cells from the patient—to manufacture rubbery connective tissue made of proteins, from which the cells are stripped away to avoid an immune reaction in patients. Some companies start with flat sheets of this tissue and roll them into tubes, while others have the cells make the stuff around a tubular mold. One company, though, is trying out a technique that made us look twice. They’re weaving the vessels from thread spun with thin strips of cultured connective tissue, Technology Review reports.

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CATEGORIZED UNDER: Health & Medicine, Technology

Watch Ants Sip Grenadine, Spheres of Algae Spin, and Other Small-Scale Spectacles in These Movies

By Valerie Ross | February 7, 2012 3:20 pm

The many-times-magnified photos of the Nikon Small World photomicrography contest entrance us year after year, with mesmerizing close-ups of nature’s microscopic marvels. Now, in the first Small World in Motion movie competition, we get to see the world’s wee wonders in action. The three winning films and eleven honorable mentions chronicle circulating blood, budding yeast, gestating eggs, and more.

First Place: This time-lapse video, at 10x magnification, traces the path of ink injected into an artery of a three-day-old chick embryo. As the ink spreads through the chick’s vascular system, the branching blood vessels and beating heart become clearly visible.

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CATEGORIZED UNDER: Living World, Technology
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