Which division accelerates activity of smooth muscles?

• A. Parasympathetic
• B. Sympathetic
• C. Somatic Nervous System
• D. Enteric

Answer: (B)

Smooth muscle activity in the gastrointestinal tract is controlled primarily by the enteric nervous system, the gut’s own network of neurons. This intrinsic system coordinates and can speed up contractions of the smooth muscle to drive peristalsis and segmentation. While parasympathetic input enhances gut motility by increasing acetylcholine release that acts on this enteric circuitry, the accelerative control is essentially exerted by the enteric nervous system itself. In contrast, the sympathetic division generally slows GI smooth-muscle activity, and the somatic nervous system controls skeletal (not smooth) muscle. So, the division that directly accelerates smooth-muscle activity in the gut is the enteric nervous system.