As a result, the postsynaptic parasympathetic nerve fibers are very short.

ACh is secreted by parasympathetic nerve fibers of both the short and long reflex pathways.

Incoming parasympathetic nerve fibers form synapses with the dendrites of nerve cells within the ganglion.

In addition, release of acetylcholine by the parasympathetic nerve fibers of the vagus nerve also stimulate its secretion.

The motor root carries presynaptic parasympathetic nerve fibers (GVE) that terminate in the ganglion by synapsing the postsynaptic fibers traveling to target organs.

This native rate is constantly modified by the activity of sympathetic and parasympathetic nerve fibers, so that the average resting cardiac rate in adult humans is about 70 beats per minute.

Parasympathetic nerve fibers arise from the central nervous system with the S2, S3, and S4 spinal nerves and from the third, seventh, ninth, and tenth cranial nerves.

The parasympathetic nerve fibers, on the contrary, travel to ganglia within the organ they are aiming at; as a result, the preganglionic fibers are quite long and the postganglionic fibers very short.

The parasympathetic nerve fibers, on the other hand, act to slow the heartbeat, contract the pupil of the eye and the bronchi of the lungs and stimulate the activity of the alimentary canal muscles.

As a result of severance and inappropriate regeneration, the parasympathetic nerve fibers may switch course, resulting in "gustatory Sweating" or sweating in the anticipation of eating, instead of the normal salivatory response.

Sympathetic innervation to the blood vessels of the mucosa causes them to constrict, while the control of secretion by the mucous glands is carried on postganglionic parasympathetic nerve fibers originating from the facial nerve.

The ethmoidal air cells receive sensory fibers from the anterior and posterior ethmoidal nerves, and the orbital branches of the pterygopalatine ganglion, which carry the postganglionic parasympathetic nerve fibers for mucous secretion from the facial nerve.

The mucous membrane in this sinus is innervated by the supraorbital nerve, which carries the postganglionic parasympathetic nerve fibers for mucous secretion from the ophthalmic nerve and supplied by the supraorbital artery and anterior ethmoidal artery.

This is because the parasympathetic nerve fibers within CNIII that influence pupillary size are found on the periphery of the nerve (in terms of a cross sectional view), which makes them less susceptible to ischemic damage (as they are closer to the vascular supply).