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Ultrastructure of moth alary muscles and their attachment to the heart wall

1968; Elsevier BV; Volume: 14; Issue: 11 Linguagem: Inglês

10.1016/0022-1910(68)90088-7

1879-1611

Joseph W. Sanger, Frances V. McCann,

Hemiptera Insect Studies

Evidence is presented to show that the alary muscles of the adult moth Hyalophora cecropia have ultrastructural characteristics of striated muscle cells. A-Band width averages 5·5 μ and ten to twelve thin filaments are localized around each thick filament. There is, however, a wide variation in the diameter of the thick filaments, i.e. 100 to 325 Å. The alary muscles share certain structural features with 'slow' striated muscles in the diminutive number of transverse tubules and reduced sarcoplasmic reticulum. The muscle fibres send out branches which are joined to the heart wall by means of a myomuscular junction, the physiological significance of which is discussed.