Z disc ultrastructure in scutal depressor fibers of the barnacle.
The ultrastrlucture of Z discs in nonglycerinated, striated muscle fibers of the barnacle Balanus nubilus Darwin was examined in contracted, resting, and stretched preparations. At all sarcomnere lengths, the Z discs are perforated sheets comprised of "Z rimns" and "Z perforations," extending continuously across the myofibril; the dimensions of the rims and perforations change with changes in sarcomere length. Accordingly, with shortening of the sarcomere, there was an accompanying decrease in the transverse width of the Z rims and an increase in the diameter of the Z perforations.
D000818:Animals; D003445:Crustacea; D008854:Microscopy, Electron; D009119:Muscle Contraction; D009210:Myofibrils / Q000033:anatomy & histology*