Functions of cranial nerves 9 and 10
What are the functions of cranial nerves IX and X (glossopharyngeal–vagal complex).
Cranial nerve IX (the glossopharyngeal nerve) and cranial nerve X (the vagus nerve) are usually considered together because of their overlapping functions. Both cranial nerves travel together intracranially, and both exit the cranial vault through the jugular foramen.
The nucleus ambiguus innervates the volitional muscles of the pharynx through both cranial nerves IX and X, and the larynx via cranial nerve X. Sensation from the larynx enters the medulla via cranial nerve X to terminate in the nucleus solitarius.
Taste fibers from the posterior one-third of the tongue travel via cranial nerve IX, and taste from the epiglottis via cranial nerve X. They terminate in the gustatory nucleus.
Cranial nerve IX also supplies parasympathetic innervation to the parotid, originating in the inferior salivatory nucleus.
Branches of cranial nerve X, the vagus nerve, continue beyond the larynx to innervate the heart, lungs, and abdominal viscera, providing primarily parasympathetic input.
