Question

Mrs. Smith comes into her doctor's office complaining of significant dry mouth. Knowing that salivary secretions are dependent on the effects of parasympathetic stimulation, the doctor decides to run some tests and finds the following. − − Both the preganglionic and postganglionic neurons of the parasympathetic nervous system release neurotransmitter at normal levels upon direct stimulation − − The salivary glands are capable of producing and secreting saliva when stimulated directly with an external stimulus. What possible pathology of the parasympathetic nervous system might explain Mrs. Smith's dry mouth? Defend your explanation using your knowledge of the functionality of the parasympathetic nervous system. Type your answer below

Answer 1

When it comes to Autonomic nervous system, Parasympathetic control is more important than sympathetic control.

The parasympathetic outflow is coordinated through centers in the medulla, and innervation occurs through the facial and glossopharyngeal nerves. Afferent information from the mouth, tongue, nose and conditioned reflexes are integrated within the brain and parasympathetic stimulation occurs in the presence of food.

In this case, pathology may be in afferent part of reflex; in taste or mastication signaling nerves, So sensations of taste or chewing are unable to reach salivary nucleis in brain.

Efferent system is intact in this case so direct stimulation is causing secretion of saliva and leading to salivation.