Shaad F U, Qayyum M A
Acta Anat (Basel). 1975;93(3):399-410. doi: 10.1159/000144516.
Anatomy, histology and innervation of the heart of spiny lizard, U. hardwickii have been described. The heart is typically reptilian and comprises four chambers: sinus venosus, two atria and a ventricle. The sinus venosus is a small, thin-walled chamber present on the dorsal side of right atrium. The sinuatrial opening is protected by a pair of valves. The auriculoventricular opening is also protected by a pair of muscular valves. The presence of a cardiac conducting system is reaffirmed. The conducting system comprises sinuatrial and atrioventricular nodes. The sinuatrial node is present at the sinuatrial junction very close to the interauricular septum. The atrioventricular node is quite conspicuous and located at the caudal end of the interauricular septum. The atrioventricular bundle is absent. There is present an atrioventricular cushion which serves the purpose of atrioventricular bundle. The heart is richly innervated, as is evident by the presence of a large number of nerve fibres and ganglion cells at the different levels of the heart. Both the nodes and the atrioventricular cushion are supplied by the fine nerve fibres, but ganglion cells could not be found in any one of these components. The myogenic theory of conduction systems is supported.
已对硬蜱（U. hardwickii）这种棘蜥心脏的解剖结构、组织学和神经支配进行了描述。心脏具有典型的爬行动物特征，由四个腔室组成：静脉窦、两个心房和一个心室。静脉窦是位于右心房背侧的一个小的薄壁腔室。窦房孔由一对瓣膜保护。房室孔也由一对肌肉瓣膜保护。再次证实了心脏传导系统的存在。传导系统包括窦房结和房室结。窦房结位于窦房交界处，非常靠近房间隔。房室结很明显，位于房间隔的尾端。房室束不存在。存在一个房室垫，起到房室束的作用。心脏有丰富的神经支配，这从心脏不同层面存在大量神经纤维和神经节细胞可以明显看出。两个结和房室垫都由细神经纤维供应，但在这些结构中的任何一个中都未发现神经节细胞。支持传导系统的肌源学说。
