Smodlaka H, Henry R W, Reed R B
College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766-1854, USA.
Anat Histol Embryol. 2009 Jun;38(3):161-8. doi: 10.1111/j.1439-0264.2008.00896.x. Epub 2009 Feb 26.
The ringed seal [Pusa (Phoca) hispida], as well as other seals, exhibits unique anatomical properties when compared to its terrestrial counterparts. In the ringed seal, the most conspicuous marine adaptation is the aortic bulb. This large dilatation of the ascending aorta is comparable to that found in other seal species and marine mammals. The branches of the ascending aorta (brachiocephalic trunk, left common carotid artery and left subclavian artery) are similar to those of higher primates and man. The peculiarities of the venous system are: three pulmonary veins, a pericardial venous plexus, a caval sphincter, a hepatic sinus with paired caudal vena cavae and a large extradural venous plexus. Generally, three common pulmonary veins (right, left and caudal) empty into the left atrium. The pericardial venous plexus lies deep to the mediastinal pericardial pleura (pleura pericardica) on the auricular (ventral) surface of the heart. The caval sphincter surrounds the caudal vena cava as it passes through the diaphragm. Caudal to the diaphragm, the vena cava is dilated (the hepatic sinus), and near the cranial extremity of the kidneys, it becomes biphid. The azygos vein is formed from the union of the right and left azygos veins at the level of the 5th thoracic vertebra. Cardiovascular physiological studies show some of these anatomical variations, especially of the venous system and the ascending aorta, to be modifications for diving. This investigation documents the large blood vessels associated with the heart and related structures in the ringed seal.
环斑海豹[环斑海豹属（海豹属）环斑海豹种]以及其他海豹与它们的陆生同类相比，具有独特的解剖学特征。在环斑海豹中，最显著的海洋适应性特征是主动脉球。升主动脉的这种大扩张类似于其他海豹物种和海洋哺乳动物中的情况。升主动脉的分支（头臂干、左颈总动脉和左锁骨下动脉）与高等灵长类动物和人类的分支相似。静脉系统的特点是：三条肺静脉、一个心包静脉丛、一个腔静脉括约肌、一个有成对尾腔静脉的肝窦和一个大的硬膜外静脉丛。一般来说，三条常见的肺静脉（右、左和尾侧）汇入左心房。心包静脉丛位于心脏耳状（腹侧）表面的纵隔心包胸膜（心包胸膜）深处。腔静脉括约肌在尾腔静脉穿过膈肌时环绕它。在膈肌尾侧，腔静脉扩张（肝窦），在肾脏头端附近，它分成两支。奇静脉由左右奇静脉在第5胸椎水平汇合而成。心血管生理学研究表明，这些解剖变异中的一些，尤其是静脉系统和升主动脉的变异，是为潜水而进行的适应性改变。本研究记录了环斑海豹中与心脏及相关结构相连的大血管。
