Cook Andrew C, Tran Vi-Hue, Spicer Diane E, Rob Jafrin M H, Sridharan Shankar, Taylor Andrew, Anderson Robert H, Jensen Bjarke
UCL Institute of Cardiovascular Science, London, UK.
Division of Pediatric Cardiology, Department of Pediatrics, University of Florida, Gainesville, FL, USA.
J Anat. 2017 Oct;231(4):484-499. doi: 10.1111/joa.12661. Epub 2017 Aug 1.
Differences between hearts of crocodilians and those of mammals and birds are only partly understood because there is no standardised approach and terminology for describing cardiac structure. Whereas most reptiles have an undivided ventricle, crocodilians have a fully septated ventricle. Their hearts, therefore, are more readily comparable with the hearts of mammals and birds. Here, we describe the heart of a crocodile (Crocodylus noliticus). We use the versatile sequential segmental approach to analysis, juxtaposing several key views of the crocodilian heart to the comparable views of human hearts. In crocodiles, the atrial and ventricular septums are complete but, unlike in placental mammals, the atrial septum is without an oval fossa. The myocardial component of the crocodilian ventricular septum dominates, but the membranous septum likely makes up a greater proportion than in any mammal. In the crocodile, the aortic trunk takes its origin from the left ventricle and is not wedged between the atrioventricular junctions. Consequently, there is a common atrioventricular junction, albeit with separate right and left atrioventricular valvar orifices. As in mammals, nonetheless, the crocodilian left atrioventricular valvar orifice is cranial to the right atrioventricular valvar orifice. By applying a method of analysis and terminology usually restricted to the human heart, we build from the considerable existing literature to show neglected and overlooked shared features, such as the offset between the left and right atrioventricular valvar orifices. Such commonalities are surprising given the substantial evolutionary divergence of the archosaur and synapsid lineages, and likely reflect evolutionarily shared morphogenetic programmes.
由于目前尚无标准化的方法和术语来描述心脏结构，所以人们对鳄鱼心脏与哺乳动物和鸟类心脏之间的差异仅了解了一部分。大多数爬行动物的心室没有分隔，而鳄鱼的心室则有完整的隔膜。因此，它们的心脏更容易与哺乳动物和鸟类的心脏进行比较。在此，我们描述了一条尼罗鳄（Crocodylus noliticus）的心脏。我们采用了通用的序列节段分析法，将鳄鱼心脏的几个关键视图与人类心脏的相应视图并列展示。在鳄鱼中，心房和心室隔膜是完整的，但与胎盘哺乳动物不同的是，心房隔膜没有卵圆窝。鳄鱼心室隔膜的心肌部分占主导，但膜性隔膜可能比任何哺乳动物的都占更大比例。在鳄鱼中，主动脉干起源于左心室，并不楔入房室交界处之间。因此，存在一个共同的房室交界处，尽管有单独的右房室瓣口和左房室瓣口。然而，与哺乳动物一样，鳄鱼的左房室瓣口位于右房室瓣口的头侧。通过应用一种通常仅限于人类心脏的分析方法和术语，我们在大量现有文献的基础上，展示了一些被忽视和忽略的共同特征，比如左右房室瓣口之间的偏移。鉴于主龙类和兽孔类谱系在进化上有很大差异，这些共性令人惊讶，并且可能反映了进化上共享的形态发生程序。
