Anderson Robert H, Smerup Morten, Sanchez-Quintana Damian, Loukas Marios, Lunkenheimer Paul P
Cardiac Unit, Institute of Child Health, University College, 30 Guilford Street, London, United Kingdom.
Clin Anat. 2009 Jan;22(1):64-76. doi: 10.1002/ca.20645.
The arrangement of the myocytes aggregated together within the ventricular walls has been the subject of anatomic investigation for more than four centuries. The dangers of analyzing the myocardium on the basis of arrangement of the skeletal myocytes have long been appreciated, yet some still described the ventricular myocardium in terms of a unique band extending from the pulmonary trunk to the aorta. Another current interpretation, with much support, is that the ventricular myocytes are compartmentalized in the form of sheets, albeit that the extent of division, and interrelations, of the sheets is less well explained. Histological examination, however, shows that the only muscular unit to be found within the myocardial walls is the cardiac myocyte itself. Our own investigations show that, rather than forming a continuous band, or being arranged as sheets, the myocytes are aggregated together as a three-dimensional mesh within a supporting matrix of fibrous tissue. Within the mesh of aggregated myocytes, it is then possible to recognize two populations, depending on the orientations of their long axes. The first population is aligned with the long axis of the aggregated myocytes tangential to the epicardial and endocardial borders, albeit with marked variation in the angulation relative to the ventricular equator. Correlation with measurements taken using force probes shows that these myocytes produce the major unloading of the blood during ventricular systole. The second population is aligned at angles of up to 40 degrees from the epicardium toward the endocardium. The correlation with measurements from force probes reveals that these intruding myocytes produce auxotonic forces during the cardiac cycle. The three-dimensional arrangement of the mesh also serves to account for the realignment of the myocytes that must take place during ventricular contraction so as to account for the extent of systolic mural thickening.
四个多世纪以来，心肌细胞在心室壁内聚集在一起的排列方式一直是解剖学研究的主题。人们早就认识到，基于骨骼肌细胞排列来分析心肌存在风险，但仍有人将心室心肌描述为从肺动脉干延伸至主动脉的独特条带。目前另一种得到大量支持的解释是，心室肌细胞呈片状分隔，尽管对于这些片层的分隔程度和相互关系的解释还不够完善。然而，组织学检查表明，心肌壁内唯一能发现的肌肉单位就是心肌细胞本身。我们自己的研究表明，心肌细胞并非形成连续条带或呈片状排列，而是在纤维组织的支持基质内聚集成三维网状结构。在聚集心肌细胞的网状结构中，根据其长轴方向可以识别出两类细胞。第一类细胞与聚集心肌细胞的长轴对齐，与心外膜和心内膜边界相切，尽管相对于心室赤道的角度存在显著变化。与使用力探针进行的测量结果相关分析表明，这些心肌细胞在心室收缩期产生血液的主要卸载。第二类细胞从心外膜向心内膜呈高达40度的角度排列。与力探针测量结果的相关性显示，这些侵入性心肌细胞在心动周期中产生辅助张力。网状结构的三维排列也有助于解释心室收缩期间心肌细胞必须发生的重新排列，以说明收缩期壁增厚的程度。
