MAIN HISTOLOGICAL CHARACTERISTICS OF THE MUSCLE FIBERS
Skeletal striated muscle fibers
They are shaped like long cylinders, which can be as long as the muscle to which they belong. They are multinucleated, and the nuclei are located on the periphery of the fiber, close to the plasma membrane. They have characteristic transverse bands in the cytoplasm, and for this reason it is a striated muscle.
They are shaped like long cylinders, which can be as long as the muscle to which they belong. They are multinucleated, and the nuclei are located on the periphery of the fiber, close to the plasma membrane. They have characteristic transverse bands in the cytoplasm, and for this reason it is a striated muscle.
Cardiac striated muscle fibers
They are shaped like short cylinders with one or two nuclei in the center. Their cytoplasm is transversely striated, like that of skeletal muscle. The fibers adhere to each other at their ends through sets of intercellular junctions. Each set of junctions (shown in the diagram alongside by dark lines) is called an intercalated disc. It is also called a scalariform disc because the junctions sometimes resemble the rungs of a ladder.
Smooth muscle fibers
They are spindle-shaped and their nucleus is central. Their cytoplasm has no transverse striation.
