Nervous control of the smooth muscle

Smooth muscle is controlled by the autonomic nervous system (NS), which is responsible for the involuntary control of organs. Smooth muscle fibers can be stimulated by the two different parts of the autonomic NS: the sympathetic NS and the parasympathetic NS (Figure 1), which are often antagonistic.

Figure 1. Muscle tissue innervation.

Autonomic nerves release different neurotranmsmitters to fire an action potentials that will initiate the contraction mechanism.

Besides the nervous control, smooth muscle can also contract due to hormones, pacemaker cells, drugs, or mechanical stretching.