The salivatory nuclei are two
general visceral efferent nuclei located in the caudal
pons
The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, 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 ...
, dorsal and lateral to the
facial nucleus
The facial motor nucleus is a collection of neurons in the brainstem that belong to the facial nerve ( cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius.
Structure
The nucleus is situat ...
. Their neurons give rise to
preganglionic
In the autonomic nervous system, nerve fibers from the central nervous system to the autonomic ganglion, ganglion are known as preganglionic nerve fibers. All preganglionic fibers, whether they are in the sympathetic nervous system, sympathetic d ...
parasympathetic
The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system.
The autonomic nervous system is responsible for regulat ...
nerve fibers in the control of
salivation
Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DN ...
.
[Digital version] The superior salivatory nucleus supplies fibers to the
intermediate nerve
The intermediate nerve, nervus intermedius, nerve of Wrisberg or glossopalatine nerve is the part of the facial nerve (cranial nerve VII) located between the motor component of the facial nerve and the vestibulocochlear nerve (cranial nerve VIII) ...
(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 ...
(CN VII). The inferior salivatory nucleus supplies fibers to the
glossopharyngeal nerve
The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...
(CN IX).
The nuclei may also be involved in parasympathetic control of (extracranial and intracranial) head vasculature.
Superior salivatory nucleus
The superior salivatory nucleus (or nucleus salivatorius superior) is a visceral motor
cranial nerve nucleus
A cranial nerve nucleus is a collection of neuron cell bodies (gray matter) in the brain stem that is associated with one or more of the cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nucle ...
of the
facial nerve (CN VII). It is located in the
pontine tegmentum
The pontine tegmentum, or dorsal pons, is the dorsal part of the pons located within the brainstem. The ventral part or ventral pons is known as the basilar part of the pons, or basilar pons. Along with the dorsal surface of the medulla oblonga ...
. It projects
pre-ganglionic visceral motor parasympathetic efferents (via
CN VII) to the
pterygopalatine ganglion
The pterygopalatine ganglion (aka Meckel's ganglion, nasal ganglion, or sphenopalatine ganglion) is a parasympathetic ganglion in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck, (the others being the s ...
, and
submandibular ganglion
The submandibular ganglion (or submaxillary ganglion in older texts) is part of the human autonomic nervous system. It is one of four parasympathetic ganglia of the head and neck. (The others are the otic ganglion, pterygopalatine ganglion, an ...
.
The term "lacrimal nucleus" is sometimes used to refer to a portion of the superior salivatory nucleus.
Efferents
Preganglionic
In the autonomic nervous system, nerve fibers from the central nervous system to the autonomic ganglion, ganglion are known as preganglionic nerve fibers. All preganglionic fibers, whether they are in the sympathetic nervous system, sympathetic d ...
fibers en route to the pterygopalatine ganglion (destined to ultimately innervate the lacrimal gland and the mucosal glands of the nose, palate, and pharynx) subsequently form the
greater petrosal nerve, whereas those en route to the submandibular ganglion (destined to ultimately innervate the
submandibular and
sublingual
Sublingual (List of abbreviations used in medical prescriptions, abbreviated SL), from the Latin for "under the tongue", refers to the pharmacological route of administration by which substances diffuse into the blood through Tissue (biology), t ...
salivary glands
The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of Duct (anatomy), ducts. Humans have three paired major salivary glands (Parotid gland, parotid, Submandibular gland, submandibula ...
) subsequently form the
chorda tympani
Chorda tympani is a branch of the facial nerve that carries gustatory (taste) sensory innervation from the front of the tongue and parasympathetic ( secretomotor) innervation to the submandibular and sublingual salivary glands.
Chorda tymp ...
.
Afferents
The nucleus receives cortical stimuli from the
nucleus of solitary tract
The solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, or nucleus tractus solitarii) is a series of neurons whose cell bodies form a roughly vertical column of grey matter in the medulla oblongata of the brainstem. Their axo ...
via the
dorsal longitudinal fasciculus
The dorsal longitudinal fasciculus (DLF) is a distinctive nerve tract in the midbrain. It extends from the hypothalamus rostrally to the spinal cord caudally, and contains both descending and ascending fibers.
Descending fibers arise in the hyp ...
and reflex connections.
Inferior salivatory nucleus
The inferior salivatory nucleus (or nucleus salivatorius inferior) is a cluster of
neuron
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
s in the
medulla. It is the
general visceral efferent (GVE) component of the
glossopharyngeal nerve
The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...
supplying the
parasympathetic
The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system.
The autonomic nervous system is responsible for regulat ...
input to 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 ...
for
saliva
Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which ...
tion.
It lies immediately caudal to the
superior salivatory nucleus
The salivatory nuclei are two general visceral efferent fiber, general visceral efferent Nucleus (anatomy), nuclei located in the caudal pons, dorsal and lateral to the facial nucleus. Their neurons give rise to preganglionic nerve fibers, pregan ...
and just above the upper end of the
dorsal nucleus of the vagus nerve in the medulla.
The preganglionic
parasympathetic
The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system.
The autonomic nervous system is responsible for regulat ...
fibres originate in the inferior salivatory nucleus of the
glossopharyngeal nerve
The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...
. They leave the glossopharyngeal nerve by its
tympanic branch and then pass via the
tympanic plexus
The tympanic plexus is a nerve plexus within the tympanic cavity formed upon the promontory of tympanic cavity by the tympanic nerve (branch of the inferior ganglion of glossopharyngeal nerve (CN IX)), and the superior and inferior caroticotympan ...
and the
lesser petrosal nerve
The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) nerve conveying pre-ganglionic parasympathetic secretomotor fibers for the parotid gland from the tympanic plexus to the otic g ...
to the
otic ganglion
The otic ganglion is a small parasympathetic ganglion located immediately below the foramen ovale in the infratemporal fossa and on the medial surface of the mandibular nerve. It is functionally associated with the glossopharyngeal nerve and i ...
. Here, the fibres synapse, and the postganglionic fibers pass by communicating branches to the
auriculotemporal nerve
The auriculotemporal nerve is a sensory branch of the mandibular nerve (CN V3) that runs with the superficial temporal artery and vein, and provides sensory innervation to parts of the external ear, scalp, and temporomandibular joint. The nerve a ...
, which conveys them to 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 ...
. They produce vasodilator and secretomotor effects.
Function
Parasympathetic input from fibers of the inferior salivatory nucleus stimulates the parotid gland to produce
vasodilation
Vasodilation, also known as vasorelaxation, 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. Blood vessel wa ...
and secrete
saliva
Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which ...
.
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)DiagramCluster Headache Pathogenesis*
* https://web.archive.org/web/20060907231522/http://sprojects.mmi.mcgill.ca/cns/histo/systems/cranialnerves/main.htm
{{Portal bar, Anatomy
Pons
Cranial nerve nuclei
Nervous system
Otorhinolaryngology