The mystery of a crocodile’s heart
Scientists say unusual valve may make long dives possible.
Aug. 24 — An unusual heart valve in crocodiles that has puzzled scientists for nearly 200 years has finally been explained, and the finding may reveal how crocs can stay underwater for hours. The valve recirculates oxygen-poor blood back into the bloodstream, apparently to sustain the animal’s most vital organs, researchers said.
THE SWEDISH and Australian team studied a common sal****er crocodile, focusing on a valve in its right ventricle called a cogged-teeth valve. It resembles interlocked human knuckles.
By injecting the reptile with a heart-slowing drug, they prompted the notched valve to close off an entry to the artery leading to the lungs. It acted like a shunt, diverting oxygen-poor blood away from the lungs and back into the bloodstream.
The experiment was done in the laboratory. The researchers suspect that wild crocodiles regulate blood flow in a much more complex manner by opening and closing the valve when they submerge for long durations.
“We believe they’re using this valve to ration their oxygen when they’re underwater,” said Michael Axelsson, an associate professor of zoophysiology at the University of Goteborg in Sweden.
The research appears in Thursday’s issue of the journal Nature.
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Alien - Administrator / Owner
["Everything was true. God was an alien. Oz really is over the
rainbow. ...and Midian is where the monsters live." -Nightbreed]
Scientists say unusual valve may make long dives possible.
Aug. 24 — An unusual heart valve in crocodiles that has puzzled scientists for nearly 200 years has finally been explained, and the finding may reveal how crocs can stay underwater for hours. The valve recirculates oxygen-poor blood back into the bloodstream, apparently to sustain the animal’s most vital organs, researchers said.
THE SWEDISH and Australian team studied a common sal****er crocodile, focusing on a valve in its right ventricle called a cogged-teeth valve. It resembles interlocked human knuckles.
By injecting the reptile with a heart-slowing drug, they prompted the notched valve to close off an entry to the artery leading to the lungs. It acted like a shunt, diverting oxygen-poor blood away from the lungs and back into the bloodstream.
The experiment was done in the laboratory. The researchers suspect that wild crocodiles regulate blood flow in a much more complex manner by opening and closing the valve when they submerge for long durations.
“We believe they’re using this valve to ration their oxygen when they’re underwater,” said Michael Axelsson, an associate professor of zoophysiology at the University of Goteborg in Sweden.
The research appears in Thursday’s issue of the journal Nature.
Want to learn more?
----------------------------
Alien - Administrator / Owner
["Everything was true. God was an alien. Oz really is over the
rainbow. ...and Midian is where the monsters live." -Nightbreed]