Medical Neurosciences 731 Afferent Home
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SUPERIOR SALIVATORY AND LACRIMAL NUCLEI

We have already discussed two PREGANGLIONIC PARASYMPATHETIC (visceromotor) nuclei, the dorsal motor nucleus X (C.N. X) and the inferior salivatory nucleus (C.N. IX). Another area in the brain stem that contains preganglionic parasympathetic cell bodies is the SUPERIOR SALIVATORY-LACRIMAL nucleus. These cells lie in the pons, just medial to the motor VII. Like the inferior salivatory nucleus, we cannot identify the superior salivatory and lacrimal nuclei.

Preganglionic parasympathetic axons arising from cells in the superior salivatory nucleus end within the SUBMANDIBULAR GANGLION. Short postganglionic fibers then pass to the sublingual and submandibular glands where they stimulate secretion. Preganglionic parasympathetic axons arising from cells in the lacrimal nucleus terminate in the PTERYGOPALATINE ganglion. Postganglionic axons then pass to the lacrimal gland to stimulate secretion.

You should remember that the inferior salivatory lies medial to nucleus ambiguus in the medulla. A lesion involving this nucleus will result in the loss of salivation from the ipsilateral parotid gland. In contrast, the superior salivatory and lacrimal nuclei lie medial to motor VII. For our PROBLEM SOLVING, any lesion that includes motor VII, AND THE REGION IMMEDIATELY MEDIAL TO IT, will result in motor VII problems PLUS a lack of saliva secretion from the ipsilateral submandibular and sublingual glands, and the loss of tearing from the ipsilateral lacrimal gland.



You should also be aware of what is called the intermediate nerve of cranial VII. This nerve contains all axons associated with this cranial nerve EXCEPT those arising from MOTOR VII. This leaves the (1) preganglionic parasympathetic fibers to the superior salivatory nucleus and the lacrimal nucleus; (2) fibers conveying taste whose cell bodies lie in the geniculate ganglion and (3) the somatic sensory fibers conveying information from the “EAR” (whose cell bodies also lie in the geniculate ganglion and whose central processes enter the spinal tract V).







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