The three-chambered frog heart mixes oxygenated and deoxygenated blood in the ventricle. Therefore, the body never receives fully oxygen-rich blood. In turtles, where a septum begins to form and separate the ventricles, the body receives slightly richer blood in oxygen. It is only in the warm-blooded model, in birds and mammals, that the two circulatory systems become fully separate sending low-pressure pumping to the lungs, and a high-pressure flow of blood to the rest of the body. In this model, the animal's muscles receive fully oxygenated blood.

Full story at:
http://www.nsf.gov/news/news_summ.jsp?cntn_id=115520

Accolades:
“The web feature is great, and I liked the video very much. I hope this will be informative to many viewers. Thanks again for doing this, this really helps spread our science to the general public, which is always a challenge.”

--Benoit Bruneau
Gladstone Institute of Cardiovascular Disease

“This is fantastic! You're a great science writer.... I'm hugely impressed, Zina...I knew you could do the graphics, but had no idea you were a wiz with the text....really cool piece.”

--Joshua Chamot
Public Affairs Specialist
National Science Foundation

“Really beautiful work, Zina!!!”

--Andrew Abalahin
San Diego State University

Also featured in:
PhysOrg
http://www.physorg.com/news171116708.html