Duan Deyong, Yu Sijiu, Cui Yan, Li Chaoxu
Laboratory of Animal Anatomy & Tissue Embryology, Department of Basic Veterinary Medicine, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu, China.
Laboratory of Molecular Physiology, Department of Basic Veterinary Medicine, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan, China.
J Morphol. 2017 Jul;278(7):975-986. doi: 10.1002/jmor.20691. Epub 2017 Apr 26.
We studied the morphology of the atrioventricular conduction system (AVCS) and Purkinje fibers of the yak. Light and transmission electron microscopy were used to study the histological features of AVCS. The distributional characteristics of the His-bundle, the left bundle branch (LBB), right bundle branch (RBB), and Purkinje fiber network of yak hearts were examined using gross dissection, ink injection, and ABS casting. The results showed that the atrioventricular node (AVN) of yak located in the right side of interatrial septum and had a flattened ovoid shape. The AVN of yak is composed of the slender, interweaving cells formed almost entirely of the transitional cells (T-cells). The His-bundle extended from the AVN, and split into left LBB and RBB at the crest of the interventricular septum. The LBB descended along the left side of interventricular septum. At approximately the upper 1/3 of the interventricular septum, the LBB typically divided into three branches. The RBB ran under the endocardium of the right side of interventricular septum, and extended to the base of septal papillary muscle, passed into the moderator band, crossed the right ventricular cavity to reach the base of anterior papillary muscle, and divided into four fascicles under the subendocardial layer. The Purkinje fibers in the ventricle formed a complex spatial network. The distributional and cellular component characteristics of the AVCS and Purkinje fibers ensured normal cardiac function.
我们研究了牦牛的房室传导系统（AVCS）和浦肯野纤维的形态。运用光镜和透射电子显微镜来研究AVCS的组织学特征。通过大体解剖、墨水注射和ABS铸型法，检查牦牛心脏希氏束、左束支（LBB）、右束支（RBB）和浦肯野纤维网的分布特征。结果显示，牦牛的房室结（AVN）位于房间隔右侧，呈扁平椭圆形。牦牛的AVN由几乎完全由移行细胞（T细胞）形成的细长、交织的细胞组成。希氏束从AVN发出，在室间隔嵴处分为左LBB和RBB。LBB沿室间隔左侧下行。在室间隔大约上1/3处，LBB通常分为三个分支。RBB走行于室间隔右侧心内膜下，延伸至间隔乳头肌基部，进入节制索，穿过右心室腔到达前乳头肌基部，并在心内膜下层分为四个分支。心室内的浦肯野纤维形成复杂的空间网络。AVCS和浦肯野纤维的分布及细胞成分特征确保了心脏的正常功能。
