Final answer:
Parasympathetic innervation in gastrointestinal muscle is excitatory, contributing to increased GI secretion and motility.
Step-by-step explanation:
The parasympathetic innervation in gastrointestinal muscle is excitatory. Activation of the parasympathetic nervous system, often referred to as the "rest-and-digest" response, increases GI secretion and motility. This is achieved by stimulating neurons of the enteric nervous system, which is responsible for regulating digestive function.