Live from AARC: The Land Before Respiratory
David J. Pierson, MD, FAARC, admitted his talk at the AARC meeting covered a "somewhat unusual topic," and very little from it could be applied to the bedside. But, then again, how can we not be fascinated by massive creatures that ruled the world for eons, he reasoned during "The Cardiopulmonary Physiology of Dinosaurs," the 35th Donald F. Egan Scientific Memorial Lecture.
Paleontologists and physiologists had little to do with each other in the past, but that disconnect has changed as of late, said Pierson, professor of medicine at the University of Washington, Seattle. A search on PubMed for the terms "dinosaurs" and "physiology" between 1990 and 2000 revealed only 13 studies. That number ballooned to 208 for papers published since 2000.
Information on dinosaur physiology comes from several areas, including: the fossil record, geologic clues to their environment, coproliths, tracks, comparisons with living animals, and modeling. With these clues, researchers have sought to answer basic questions on how dinosaurs functioned.
For example, the head of some dinos stood 25 feet above their heart. How could they possibly perfused their brain, he asked. The leading theories state dinosaurs probably had a four-chamber heart and extremely high blood pressure. Also, they probably didn't raise their heads as high as investigators once thought.
Another puzzler Pierson described: How could creatures with 35-foot-long necks breathe? Most likely, birds evolved from dinosaurs and some of the ancient beasts had an avian-type respiratory system.