Compared to striated muscle tissue, smooth muscle cells have a less ordered arrangement of actin and myosin filaments. They also do not form sarcomere structures.

The longitudinal section (4,800X) demonstrates that smooth muscle cells are fusiform here, they contain bundles of thin myofilaments; between the muscle cells, there is a fine network of collagen and elastic fibers, which replaces skeletal structures in the muscle stratum. The fibers are produced by the same cells.

A larger zooming (30,000X) allows a better, more detailed study of the distribution of contractile elements in the smooth muscle cell cytoplasm. Myofilaments are oriented in different directions, hence contracting cells both shorten and change their shape. Thin actin filaments #1, #2 attach to some cytoplasmic structures with the help of associated proteins, thereby forming dense bodies #1, #2 (an equivalent structure of Z lines of a striated myofibril); they may also attach to certain cell membrane condensations ( dense plaques). Excitation is conducted by the system of caveolae. These are flask-shaped invaginations of sarcolemma. The conducting apparatus alsi involves intracellular membrane vesicles, which are solitary or constituting branched structures; they providing for calcium ion storage and their transfer to contractile filaments.

The walls of internal organs contain smooth muscle cells that operate together as bundles (transverse section, 9,000X). They are functionally linked due to participation of certain clusters containing gap junctions (nexuses) #1, #2, #3, #4. The junctions allow for propagation of depolarization wave from one cell to another.