A Comparative Study of Piscine Heart Function

9316621格雷厄姆这项研究将检查无骨鳃动物（鲨鱼和鳐鱼）和硬骨鱼类的心腔功能。鱼类的心脏结构由一个单管组成，它被分成四个“串联”的腔室：静脉窦、心房、心室和动脉圆锥或球。在鲨鱼中，所有这些，包括圆锥，都是可收缩的，而在大多数硬骨鱼类中，球体是弹性的。鱼类的心脏腔的排列不同于哺乳动物，包括人类，有四个平行排列的腔（两个心房，两个心室）。本研究将检查鲨鱼（角鲨）和硬骨鱼（大比目鱼）在心脏周期中心房和心室的相互作用。由于哺乳动物的腔室平行排列，腔室相互作用的研究由于共用中央心脏壁的四个独立收缩元件的作用而变得复杂。因此，fish提供了更简单、串联的腔室动力学的优势，这可以量化腔室相互作用对心脏泵体积和效率的影响。鱼类心脏的其他几个特征使其成为哺乳动物心脏功能的重要模型，并将在本研究中进行研究。与哺乳动物光滑的心肌壁相反，鱼类有海绵状的心肌壁。此外，鲨鱼与硬骨鱼的不同之处在于，它们有一个可收缩的圆锥，而不是有弹性的球体。最后，鲨鱼缺乏心脏交感神经支配，这与心脏移植病人的情况相似。＊＊＊

9316621 Graham This study will examine heart-chamber functions in elasmobranchs (sharks and rays) and bony fishes. In fishes the heart structure consists of a single tube that is divided into four "in-series" chambers, the sinus venosus, the atrium, the ventricle, and the conus or bulbus arteriosus. In sharks, all of these, including the conus, are contractile whereas in most bony fishes, the bulbus is elastic. The cardiac chamber arrangement in fishes differs from that of mammals, including man, where there are four chambers (two atria, two ventricles) arranged in parallel. This study will examine atrial and ventricular interactions during the cardiac cycle in both sharks (hornshark) and teleost (halibut) fishes. Because of the parallel arrangement of chambers in mammals, study of chamber interaction is complicated by the actions of the four separate contractile elements that share a common central heart wall. Fishes thus offer the advantage of simpler, in-series chamber dynamics and this allows quantification of chamber-interaction effects on the volume and efficiency of the cardiac pump. Several other fish-heart features make it an important model for the mammal heart function and will be investigated in this study. Fishes have a spongy inner myocardial wall, as opposed to the smooth wall of mammals. Also, sharks differ from teleosts in having a contractile conus as opposed to an elastic bulbus. Finally, sharks lack a sympathetic cardiac innervation which parallels the condition in cardiac transplant patients. ***