21. The sphincter pupillae is stimulated through muscarinic receptors by the parasympathetic nervous system. 22. Occasionally, supraventricular arrhythmias observed in MVP are associated with increased parasympathetic tone. 23. Preganglionic parasympathetic fibres arise in the superior salivary nucleus of the pontine tegmentum. 24. These parasympathetic preganglionic fibers come from the facial nerve ( CN VII ). 25. However, in general, parasympathetic stimulation increases secretion of all digestive enzymes. 26. Postganglionic cell refers to parasympathetic neurons which receive information from the preganglionic fibers. 27. Pupil size is therefore under the dual control of sympathetic and parasympathetic nerves. 28. There are roughly twice as many incoming parasympathetic fibers as outgoing parasympathetic fibers. 29. There are roughly twice as many incoming parasympathetic fibers as outgoing parasympathetic fibers. 30. Although such pacemaker potentials have a parasympathetic nerves.
