Mrs. Smith comes into her doctor’s office complaining of significant dry mouth.

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.

Explanation / Answer

In Autonomic nervous system, Parasympathetic control is far more important than sympathetic control.

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

In this case, Mr. Smith, pathology might be in afferent part of reflex that is in taste or mastication signaling nerves.

So sensation of taste or mastication are unable ro deach salivary nucleis in brain.

Efferent system is intact so direct stimulatiom is causing secretion of saliva and leading to salivation.

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