A Comparative Study of Piscine Heart Function

9316621格雷厄姆这项研究将研究棘鳃类(鲨鱼和银鱼)和硬骨鱼的心腔功能。鱼的心脏结构由一根被分成四个“串联”腔的单管组成，分别是静脉窦、心房、脑室和动脉圆锥。在鲨鱼中，包括圆锥在内的所有这些都是收缩的，而在大多数多骨鱼类中，球茎是有弹性的。鱼类的心腔排列不同于哺乳动物，包括人类，哺乳动物有四个心腔(两个心房，两个心室)平行排列。这项研究将研究鲨鱼(角鲨)和硬骨鱼(大比目鱼)在心脏周期中的房室相互作用。由于哺乳动物心腔的平行排列，心腔相互作用的研究因四个独立的收缩元件共享一个中央心壁的作用而变得复杂。因此，FISH提供了更简单的串联腔体动力学的优势，这允许量化腔体相互作用对心脏泵的体积和效率的影响。其他几个鱼心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。鱼有一层海绵状的心肌内壁，与哺乳动物的光滑壁不同。此外，鲨鱼与硬骨鱼的不同之处在于，它有一个可收缩的圆锥体，而不是弹性球茎。最后，鲨鱼缺乏交感神经，这与心脏移植患者的情况类似。***

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. ***