No abstract

No abstract

The striated swim bladder muscles of the weakfish Cynoscion regalis are deep red in color but cannot be classified histologically as having typical red fibers. The muscle fibers are homogeneous and average 29.6 ± 5.3 μm in diameter, one-fifth the diameter of the adjacent hypaxialis fibers. Each muscle fiber contains thin, ribbonlike myofibrils which are radially arranged around a central core of mitochondria, glycogen, and sarcoplasmic reticulum. Myofibrils are extremely regular in pattern. Triads occur at the Z line. Numerous mitochondria and muscle nuclei are located at the periphery of each muscle fiber. The muscle fibers are multiply innervated with motor endplates distributed along their entire lengths. Well-developed folding of the postsynaptic membrane, not previously reported in fishes, is present at the motor endplate.

No abstract