Physiology Which one of the following statements regarding the regulation of gastrointestinal function is true? A The main sympathetic nerve supply to the digestive tract is the vagus. B In general, sympathetic stimulation is excitatory to digestive activity. C Salivary secretion is stimulated by both branches of the autonomic nervous system, although not to the same degree. D Parasympathetic stimulation of the salivary glands produces a saliva rich in mucus. 💡 Explanation Which one of the following statements regarding the regulation of gastrointestinal function is true? ✓ Correct Answer: C. Salivary secretion is stimulated by both branches of the autonomic nervous system, although not to the same degree.