The salivatory nuclei are the superior salivatory nucleus, and the inferior salivatory nucleus that innervate the salivary glands. They are located in the pontine tegmentum in the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is ...

. They both are examples of cranial nerve nuclei. The superior salivatory nucleus innervates the submandibular gland and the sublingual gland and is part of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

The inferior salivatory nucleus innervates the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the m ...

by way of the otic ganglion and forms the parasympathetic component of the glossopharyngeal nerve.

Superior salivatory nucleus

The superior salivatory nucleus (or nucleus salivatorius superior) of the

is a visceromotor cranial nerve nucleus located in the pontine tegmentum. It is one of the salivatory nuclei. Parasympathetic efferent fibers of the

(preganglionic fibers) arise according to some authors from the small cells of the facial nucleus, or according to others from a special nucleus of cells scattered in the reticular formation, dorso-medial to the facial nucleus – the superior salivatory nucleus. Some of the preganglionic fibers travel along the greater petrosal nerve through the pterygoid canal, where they join the postsynaptic fibers of the deep petrosal nerve to become the nerve of the pterygoid canal. These fibers synapse in the pterygopalatine ganglion, whereupon the postganglionic, postsynaptic, efferent fibers travel to innervate the lacrimal gland and the mucosal glands of the nose, palate, and pharynx. Preganglionic parasympathetic fibers are also distributed partly via the chorda tympani and

lingual nerves The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division of the trigeminal nerve (CN V3 ) and from the facial nerve (CN VII). The fibres from the trigeminal nerve ...

to the submandibular ganglion, thence by postganglionic (vasodilator) fibers to the submandibular and sublingual

salivary glands The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivar ...

. The term "lacrimal nucleus" is sometimes used to refer to a portion of the superior salivatory nucleus.

Inferior salivatory nucleus

The inferior salivatory nucleus (or nucleus salivatorius inferior) is a cluster of

neuron A neuron, neurone, or nerve cell is an membrane potential#Cell excitability, electrically excitable cell (biology), cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous ...

s in the pontine tegmentum (dorsal part of the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other bipeds lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of ...

), just above its junction with the medulla. It is the

general visceral efferent General visceral efferent fibers (GVE) or visceral efferents or autonomic efferents, are the efferent nerve fibers of the autonomic nervous system (also known as the ''visceral efferent nervous system'' that provide motor innervation to smooth mu ...

(GVE) component of the glossopharyngeal nerve supplying the parasympathetic input to the

for salivation. It lies immediately caudal to the superior salivatory nucleus and just above the upper end of the dorsal nucleus of the vagus nerve in the medulla. The preganglionic parasympathetic fibres originate in the inferior salivatory nucleus of the glossopharyngeal nerve. They leave the glossopharyngeal nerve by its tympanic branch and then pass via the tympanic plexus and the lesser petrosal nerve to the otic ganglion. Here, the fibres synapse, and the postganglionic fibers pass by communicating branches to the

auriculotemporal nerve The auriculotemporal nerve is a branch of the mandibular nerve (CN V3) that runs with the superficial temporal artery and vein, and provides sensory innervation to various regions on the side of the head. Structure Origin The auriculotemp ...

, which conveys them to the

. They produce vasodilator and secretomotor effects.

Function

Parasympathetic input from fibers of the inferior salivatory nucleus stimulates the parotid gland to produce

vasodilation Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstricti ...

and secrete saliva.

Additional images

File:Gray696.png, The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue. File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral view.

References

Bibliography

External links

*
Diagram (look for #3)

Diagram

Cluster Headache Pathogenesis
* * https://web.archive.org/web/20060907231522/http://sprojects.mmi.mcgill.ca/cns/histo/systems/cranialnerves/main.htm {{Rhombencephalon Pons