Finally, an intermediate form - the fast oxidative fibers , are intermediate between the two extremes. This form responds well to training. Smooth Muscle is small and tapered on the ends. Often found in thin layers surrounding hollow, tubular, viscera. These have the ability to contract slowly and for extended periods of time, and over a very wide range of cell lengths.
Some forms are self-exciting and can spread excitation from cell to cell in a direct fashion.
Other forms require neural stimulation to contract. Cardiac Muscle is a specialized form of striated muscle. The cells are very small and divided. Excitation can spread from cell to cell and any cell can potentially become self-exciting, if left alone long enough. Cells have a very large proportion of their volume devoted to mitochondria.