@admin said in Station - parotid gland:
Parasympathetic
Parasympathetic (secretomotor) innervation
The parasympathetic supply increases the production of watery saliva. Its pathway is long and complex, beginning with the glossopharyngeal nerve (CN IX).
Origin: The preganglionic parasympathetic fibers arise from the inferior salivatory nucleus in the brainstem.
Course: The fibers travel along the glossopharyngeal nerve and a small branch called the tympanic nerve, which passes through the middle ear.
Synapse: The fibers continue as the lesser petrosal nerve and synapse in the otic ganglion, which is a collection of nerve cell bodies near the base of the skull.
Supply: The postganglionic fibers then "hitchhike" along the auriculotemporal nerve (a branch of the trigeminal nerve) to reach and innervate the parotid gland. (Hence sometimes post parotidectomy when the great auricular nerve is sacrified or injured - it causes Frey's syndrome - where regenerating of parasympathetic fibers accidentally "rewire" themselves to connect with the sympathetic pathways that lead to the skin's sweat glands and blood vessels
Sympathetic innervation
The sympathetic supply reduces saliva production, causing a thicker, more viscous saliva via vasoconstriction.
• The postganglionic sympathetic fibers originate from the superior cervical ganglion and travel to the gland along the external carotid artery.
Sensory innervation
The parotid gland receives its sensory supply from two nerves.
• Auriculotemporal nerve: This nerve provides general sensory innervation directly to the substance of the gland.
• Great auricular nerve: This nerve, a branch of the cervical plexus (C2 and C3), supplies the sensory innervation to the tough fascia or capsule of the parotid gland.
