Eichelberg H
Cell Tissue Res. 1977 Dec 28;185(4):547-55. doi: 10.1007/BF00220658.
The anterior and the posterior drum muscles of the piranha resemble each other in all essential fine structural aspects: myofibrils are slender; sarcomeres are short compared with those of other drum muscles; mitochondria, located in the periphery of the fibers, are numerous and show an irregular internal structure; and the sarcoplasmic reticulum is abundant. Triads appear at the level of the Z lines. The drum muscles have many motor endplates, which, however, lack the characteristic junctional-fold apparatus. No lipid substances could be demonstrated in these muscles. In the posterior drum muscle the fibers depart from their orderly longitudinal arrangement at irregular intervals.
肌原纤维细长；与其他鼓肌相比，肌节较短；位于纤维外周的线粒体数量众多且内部结构不规则；肌浆网丰富。三联体出现在Z线水平。鼓肌有许多运动终板，然而，这些终板缺乏典型的连接褶装置。在这些肌肉中未发现脂质物质。在后鼓肌中，纤维以不规则的间隔偏离其有序的纵向排列。
