據(jù)1月15日的《科學(xué)》雜志報(bào)道說,，短吻鱷的肺與鳥的肺類似，即空氣是沿著一個(gè)單向通路進(jìn)行流通,，而非進(jìn)出一個(gè)盲端通路,。 這種肺的結(jié)構(gòu)一般被認(rèn)為是鳥類所獨(dú)有的專門結(jié)構(gòu)，因?yàn)轼B類在飛翔的時(shí)候需要大量的氧氣,。但新的研究結(jié)果提示,，這種單向的氣流模式最有可能是起源于鳥類和短吻鱷所共有的祖先，例如早期的爬行動(dòng)物,，或三疊紀(jì)中的“祖龍”,。
Collen Farmer 和Kent Sanders研究了美洲短吻鱷肺內(nèi)的空氣和水流模式，他們的研究包括了活體動(dòng)物的肺以及切割下來的人工通氣的肺,。 他們發(fā)現(xiàn),，在短吻鱷中的氣流是單向的而且與鳥類極為相似，盡管現(xiàn)在仍不清楚短吻鱷究竟是如何進(jìn)行這種類型的呼吸的,，因?yàn)樗鼈儾]有鳥肺所具有的氣囊,。 文章的作者提出，這種氣流模式可追溯到三疊紀(jì)早期的祖龍,，并可能一直存在于不同的祖龍后裔之中,，即除了鱷魚和鳥類之后還包括恐龍。 這些作者進(jìn)一步猜測,，這種肺結(jié)構(gòu)可能賦予早期祖龍種群某種優(yōu)勢,，使它們能夠進(jìn)行劇烈的運(yùn)動(dòng)。（生物谷Bioon.com）
相關(guān)研究：JEB:美洲短吻鱷肺可移動(dòng)
生物谷推薦原始出處：
Science 15 January 2010: DOI: 10.1126/science.1180219
Unidirectional Airflow in the Lungs of Alligators
C. G. Farmer1,* and Kent Sanders2
The lungs of birds move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi), whereas in the lungs of mammals and presumably other vertebrates, air moves tidally into and out of terminal gas-exchange structures, which are cul-de-sacs. Unidirectional flow purportedly depends on bellowslike ventilation by air sacs and may have evolved to meet the high aerobic demands of sustained flight. Here, we show that air flows unidirectionally through parabronchi in the lungs of the American alligator, an amphibious ectotherm without air sacs, which suggests that this pattern dates back to the basal archosaurs of the Triassic and may have been present in their nondinosaur descendants (phytosaurs, aetosaurs, rauisuchians, crocodylomorphs, and pterosaurs) as well as in dinosaurs.
1 Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
2 Department of Radiology, Musculoskeletal Division, 50 North Medical Drive, Room 1A71, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA.
