Which one of the following statements regarding the regulation of gastrointestinal function is true?
The salivary glands are under the influence of both the sympathetic and parasympathetic nervous system. Parasympathetic stimulation results in a more watery secretion compared with sympathetic stimulation, which produces increased amounts of protein with reduced volume. The vagus is parasympathetic, which in general is stimulatory to gastrointestinal tract. In general, sympathetics are inhibitory to the gastrointestinal tract. (The exceptions are salivary glands.)
The main sympathetic nerve supply to the digestive tract is the vagus.
In general, sympathetic stimulation is excitatory to digestive activity.
Salivary secretion is stimulated by both branches of the autonomic nervous system, although not to the same degree.
Parasympathetic stimulation of the salivary glands produces a saliva rich in mucus.