Urethral smooth muscle relaxation

Smooth muscle is different from striated muscle. Striated muscle is innervated by the trunk nerve and has obvious motor nerve fibers. Smooth muscle is dominated by the dual nervous system of the autonomic nervous system, but no real motor nerve was found. Smooth muscle contraction is relatively dull, but it can last, and it does not lose its tension for a long time after the nerve is severed. The contraction of smooth muscle is caused by the stimulation of urine expansion. Urinary smooth muscle relaxation leads directly to urinary incontinence.