当前位置： SCI文献检索 > Respiratory Care期刊下所有文献 > The physiology of dinosaurs: circulatory and respiratory function in the largest animals ever to walk the earth.

The physiology of dinosaurs: circulatory and respiratory function in the largest animals ever to walk the earth.

Abstract：

:The cardiopulmonary physiology of dinosaurs-and especially of the long-necked sauropods, which grew much larger than any land animals before or since-should be inherently fascinating to anyone involved in respiratory care. What would the blood pressure be in an animal 12 m (40 ft) tall? How could airway resistance and dead space be overcome while breathing through a trachea 9 m (30 ft) long? The last decade has seen a dramatic increase in evidence bearing on these questions. Insight has come not only from new fossil discoveries but also from comparative studies of living species, clarification of evolutionary relationships, new evaluation techniques, computer modeling, and discoveries about the earth's ancient atmosphere. Pumping a vertical column of blood 8 m (26 ft) above the heart would probably require an arterial blood pressure > 600 mm Hg, and the implications of this for cardiac size and function have led to the proposal of several alternative cardiopulmonary designs. Diverse lines of evidence suggest that the giant sauropods were probably warm-blooded and metabolically active when young, but slowed their metabolism as they approached adult size, which diminished the load on the circulatory system. Circulatory considerations leave little doubt that the dinosaurs had 4-chambered hearts. Birds evolved from dinosaurs, and the avian-type air-sac respiratory system, which is more efficient than its mammalian counterpart, may hold the answer to the breathing problems posed by the sauropods' very long necks. Geochemical and other data indicate that, at the time the dinosaurs first appeared, the atmospheric oxygen concentration was only about half of what it is today, and development of the avian-type respiratory system may have been key in the dinosaurs' evolutionary success, enabling them to out-compete the mammals and dominate the land for 150 million years.

journal_name

Respir Care

journal_title

Respiratory care

authors

Pierson DJ

doi

10.4187/002013209793800286

subject

Has Abstract

pub_date

2009-07-01 00:00:00

pages

887-911

issue

eissn

0020-1324

issn

1943-3654

journal_volume

pub_type

在线工具

The physiology of dinosaurs: circulatory and respiratory function in the largest animals ever to walk the earth.