musculo de aspecto fibroso 7
Smooth muscle is composed of smooth muscle fibers that correspond to cells uninucleate, thin and sharp at the ends, the length of which varies between 20 and 500 mm (Figs. 1 and 2, ) This type of muscle forms the contractile portion of the wall of various organs such as digestive tract (Fig 3-) and 40 vessels;Fig 4 ) requiring a slow and sustained contraction. The cells are organized into groups, forming beams, surrounded by fibrous connective tissue containing blood vessels.