Berge P I
Cell Tissue Res. 1979 Sep 3;201(2):181-95. doi: 10.1007/BF00235056.
The ultrastructure of the heart in Chimaera monstrosa L. is described. The endocardial and the epicardial cells are similar in the three cardiac regions. Myocardial cells show small variations. The myofibred, 4--6 microns thick, contains one or a few myofibrils. Each myosin filament is surrounded by six actin filaments. The sarcomere banding pattern includes the Z-, A-, I-, M-, N-, and H-band. End-to-end attachments between myofibres are composed of alternating desmosomes and fasciae adhaerentes. Desmosomes and nexuses occur between longitudinally oriented cell surfaces. The sarcoplasmic reticulum is poorly developed but well defined. Peripheral coupling-like structures are common, T-tubules are absent. Membrane bound dense bodies occur in all regions. Areas with ribosomes and single myosin filaments are often seen. The epicardial cells have a regular hexagonal surface and are much thicker than the endocardial cells. Numerous short and few longer cytoplasmic extensions face the pericardial cavity. The flat endocardial cells contain a large nucleus and small amounts of cytoplasm.
描述了银鲛心脏的超微结构。在三个心脏区域中，心内膜细胞和心外膜细胞相似。心肌细胞有微小差异。肌纤维厚4 - 6微米，包含一条或几条肌原纤维。每条肌球蛋白丝被六条肌动蛋白丝包围。肌节带纹模式包括Z带、A带、I带、M带、N带和H带。肌纤维之间的端端连接由交替的桥粒和黏着小带组成。桥粒和连接复合体出现在纵向排列的细胞表面之间。肌浆网发育不良但界限清晰。外周类似耦联的结构常见，T小管缺失。膜结合致密体出现在所有区域。常可见到有核糖体和单条肌球蛋白丝的区域。心外膜细胞表面呈规则的六边形，比心内膜细胞厚得多。许多短的和少量较长的细胞质突起朝向心包腔。扁平的心内膜细胞含有一个大细胞核和少量细胞质。
