Crocodiles can bypass their lungs for improved digestion

February 5th, 2008 - 2:42 pm ICT by admin  

Washington, Feb 5 (ANI): A new research on American alligators’ circulation systems has shown that crocodilians bypass their lungs to improve digestion and increase chances of their long-term survival in the wild.

While it has long been known that reptiles have the ability to shunt blood past their lungs, the physiological function of this ability is poorly understood.

But now, Professor C.G. Farmer and her colleagues at the University of Utah, along with the Utah Artificial Heart Institute, were able to demonstrate through their experiments with American alligators that the bypass function is central in their digestion process, and ultimately, their survival.

After feasting, crocodilians like to find a warm place to lie down while they digest their meal. Although on the outside this behavior seems ordinary, inside their bodies an extraordinary event takes place.

According to the research, during this period of digestion, crocodilians divert blood through a special vessel that bypasses the lung, named the left aorta.

Crocodilians can chose not to use the left aorta, in which case their cardiovascular system is very much like the mammalian system.

However, when crocodilians are digesting a meal, they chose to shunt and direct CO2-rich blood straight to the stomach where glands make use of the CO2 to form gastric acid and bicarbonate. Consequently, this shunt enables crocodilians to secrete gastric acid at a rate that is approximately 10 times the highest rates measured in mammals.

If crocodilians are deprived of this ability to sidestep their lungs, their rates of acid secretion drop significantly and their ability to dissolve bone, a regular part of their normal diet, is impaired.

This inability to digest meals quickly puts crocodilians at risk of death from within, or if they are young, by predators.

Crocodilians are cold-blooded animals that rely on basking in the sun for warmth, and a warm belly is essential for high rates of acid secretion, good digestion, and rapid growth, but basking sites are not always plentiful and the biggest animals dominate these sites.

Thus it may be critical for little crocodilians to rapidly secrete acid while they have the opportunity to get warm. (ANI)

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