Trophic Effects of Nerves on Muscle . A denervated muscle cell will revert to a very slow type. It will have ACh receptors all over its membrane. Upon reinnervation, the muscle cell will become the type that the nerve cell previously served and ACh receptors will occur only under the synaptic junction at the same density that they were previously all over the cell membrane. Depolarization and refractory periods may last about 200 msec causing the muscle to remain contracted for that long.
Smooth muscle is called such because it has no striations.
Electron microscopy has not revealed a pattern of filaments in the cell. Nerve stimulation comes from autonomic nerves that lie alongside muscle cells and secrete into the extracellular fluid from varicosities in the nerves. The transmitter diffuses over several cells. This allows actin and myosin to interact. List, in order, the sequence of events in a skeletal muscle contraction.