Do muscle cells have a threshold intensity which must be reached by a stimulus if they are to fire? Do muscle cells exhibit an "all-or-nothing" property, either contracting all the way when stimulated? How can a muscle produce varying responses in reaction to a varying range of stimuli?
Like nerve cells, individual muscle fibers fire only when stimulated above their threshold intensity and exhibit the nerve cells' all-or-nothing property as well, where the stimulus either causes the fiber to contract all the way or not at all. Yet because muscles are composed of many fibers with different threshold intensities, muscles are capable of producing a varying range of responses in reaction to a varying range of stimuli.
