Salivary gland (Endocrine system)

Salivary+Glands

HYPERLINK «http://en.wikipedia.org/wiki/Latin» \o «Latin» Latin
glandulae salivariae

The salivary glands in HYPERLINK
«http://en.wikipedia.org/wiki/Mammals» \o «Mammals» mammals are
HYPERLINK «http://en.wikipedia.org/wiki/Exocrine_glands» \o «Exocrine
glands» exocrine glands that produce HYPERLINK
«http://en.wikipedia.org/wiki/Saliva» \o «Saliva» saliva . They also
secrete HYPERLINK «http://en.wikipedia.org/wiki/Amylase» \o «Amylase»
amylase , an HYPERLINK «http://en.wikipedia.org/wiki/Enzyme» \o
«Enzyme» enzyme that breaks down HYPERLINK
«http://en.wikipedia.org/wiki/Starch» \o «Starch» starch into
HYPERLINK «http://en.wikipedia.org/wiki/Glucose» \o «Glucose» glucose .
In other organisms such as HYPERLINK
«http://en.wikipedia.org/wiki/Insecta» \o «Insecta» insects , salivary
glands are often used to produce biologically important proteins like
HYPERLINK «http://en.wikipedia.org/wiki/Silk» \o «Silk» silk or glues,
and HYPERLINK «http://en.wikipedia.org/wiki/Fly» \o «Fly» fly
salivary glands contain HYPERLINK
«http://en.wikipedia.org/wiki/Polytene_chromosome» \o «Polytene
chromosome» polytene chromosomes that have been useful in HYPERLINK
«http://en.wikipedia.org/wiki/Genetics» \o «Genetics» genetic
research.

Histology

The glands are enclosed in a capsule of HYPERLINK
«http://en.wikipedia.org/wiki/Connective_tissue» \o «Connective tissue»
connective tissue and internally divided into HYPERLINK
«http://en.wikipedia.org/wiki/Lobe» \o «Lobe» lobules . Blood vessels
and nerves enter the glands at the HYPERLINK
«http://en.wikipedia.org/wiki/Hilum» \o «Hilum» hilum and gradually
branch out into the lobules.

Ducts

In the duct system, the lumens formed by HYPERLINK
«http://en.wikipedia.org/wiki/Intercalated_ducts» \o «Intercalated
ducts» intercalated ducts , which in turn join to form HYPERLINK
«http://en.wikipedia.org/wiki/Striated_ducts» \o «Striated ducts»
striated ducts . These drain into ducts situated between the lobes of
the gland (called HYPERLINK
«http://en.wikipedia.org/wiki/Interlobar_ducts» \o «Interlobar ducts»
interlobar ducts or excretory ducts).

All of the human salivary glands terminate in the mouth, where the
saliva proceeds to aid in digestion. The saliva that salivary glands
release is quickly inactivated in the stomach by the acid that is
present there.

Anatomy

The salivary glands are situated at the entrance to the HYPERLINK
«http://en.wikipedia.org/wiki/Gastrointestinal_system» \o
«Gastrointestinal system» gastrointestinal system to help begin the
process of digestion.

Parotid Glands

The HYPERLINK «http://en.wikipedia.org/wiki/Parotid_glands» \o
«Parotid glands» parotid glands are a pair of glands located in the
HYPERLINK «http://en.wikipedia.org/wiki/Subcutaneous_tissues» \o
«Subcutaneous tissues» subcutaneous tissues of the face overlying the
HYPERLINK «http://en.wikipedia.org/wiki/Mandibular_ramus» \o
«Mandibular ramus» mandibular ramus and anterior and inferior to the
HYPERLINK «http://en.wikipedia.org/wiki/External_ear» \o «External ear»
external ear . The secretion produced by the parotid glands is
HYPERLINK «http://en.wikipedia.org/wiki/Serous» \o «Serous» serous in
nature, and enters the HYPERLINK
«http://en.wikipedia.org/wiki/Oral_cavity» \o «Oral cavity» oral cavity
through the HYPERLINK «http://en.wikipedia.org/wiki/Stensen%27s_duct»
\o «Stensen’s duct» Stensen’s duct after passing through the
HYPERLINK «http://en.wikipedia.org/wiki/Intercalated_ducts» \o
«Intercalated ducts» intercalated ducts which are prominent in the
gland. Despite being the largest pair of glands, only approximately 25%
of saliva is produced by the glands.

Submandibular Glands

The HYPERLINK «http://en.wikipedia.org/wiki/Submandibular_gland» \o
«Submandibular gland» submandibular glands are a pair of glands
located beneath the floor of the mouth, superior to the HYPERLINK
«http://en.wikipedia.org/wiki/Digastric_muscle» \o «Digastric muscle»
digastric muscles . The secretion produced is a mixture of both
HYPERLINK «http://en.wikipedia.org/wiki/Serous» \o «Serous» serous and
HYPERLINK «http://en.wikipedia.org/wiki/Mucous» \o «Mucous» mucous
and enters the HYPERLINK «http://en.wikipedia.org/wiki/Oral_cavity» \o
«Oral cavity» oral cavity via HYPERLINK
«http://en.wikipedia.org/wiki/Wharton%27s_duct» \o «Wharton’s duct»
Wharton’s ducts . Approximately 70% of saliva in the oral cavity is
produced by the submandibular glands, even though they are much smaller
than the HYPERLINK «http://en.wikipedia.org/wiki/Parotid_glands» \o
«Parotid glands» parotid glands .

Sublingual Gland

The HYPERLINK «http://en.wikipedia.org/wiki/Sublingual_gland» \o
«Sublingual gland» sublingual glands are a pair of glands located
beneath the floor of the mouth anterior to the HYPERLINK
«http://en.wikipedia.org/wiki/Submandibular_gland» \o «Submandibular
gland» submandibular glands . The secretion produced is mainly
HYPERLINK «http://en.wikipedia.org/wiki/Mucous» \o «Mucous» mucous in
nature, however it is categorized as a mixed gland. Unlike the other two
major glands, the ductal system of the sublingual glands do not have
striated ducts, and exit from 8-20 excretory ducts. Approximately 5% of
saliva entering the oral cavity come from these glands.

Minor Salivary Glands

There are over 600 minor salivary glands located throughout the
HYPERLINK «http://en.wikipedia.org/wiki/Oral_cavity» \o «Oral cavity»
oral cavity within the HYPERLINK
«http://en.wikipedia.org/wiki/Lamina_propria» \o «Lamina propria»
lamina propria of the HYPERLINK
«http://en.wikipedia.org/wiki/Oral_mucosa» \o «Oral mucosa» oral mucosa
. They are 1-2mm in diameter and unlike the other glands, they are not
encapsulated by HYPERLINK
«http://en.wikipedia.org/wiki/Connective_tissue» \o «Connective tissue»
connective tissue only surrounded by it. The gland is usually a number
of HYPERLINK «http://en.wikipedia.org/wiki/Acini» \o «Acini» acini
connected in a tiny lobule. A minor salivary gland may have a common
excretory duct with another gland, or may have its own excretory duct.
Their secretion is mainly mucous in nature (except for HYPERLINK
«http://en.wikipedia.org/wiki/Von_Ebner%27s_glands» \o «Von Ebner’s
glands» Von Ebner’s glands ) and have many functions such as coating
the oral cavity with HYPERLINK «http://en.wikipedia.org/wiki/Saliva»
\o «Saliva» saliva . Problems with dentures are usually associated with
minor salivary glands. HYPERLINK
«http://en.wikipedia.org/wiki/Salivary_gland» \l «cite_note-Cate3-0» \o
«» [1]

Von Ebner’s Glands

HYPERLINK «http://en.wikipedia.org/wiki/Von_Ebner%27s_glands» \o «Von
Ebner’s glands» Von Ebner’s glands are glands found in HYPERLINK
«http://en.wikipedia.org/wiki/Circumvallate_papillae» \o «Circumvallate
papillae» circumvallate papillae of the tongue. They secrete a serous
fluid that begin lipid hydrolysis. They are an essential component of
HYPERLINK «http://en.wikipedia.org/wiki/Taste» \o «Taste» taste .

Innervation

Salivary glands are innervated, either directly or indirectly, by the
HYPERLINK «http://en.wikipedia.org/wiki/Parasympathetic_nervous_system»
\o «Parasympathetic nervous system» parasympathetic and HYPERLINK
«http://en.wikipedia.org/wiki/Sympathetic_nervous_system» \o
«Sympathetic nervous system» sympathetic arms of the HYPERLINK
«http://en.wikipedia.org/wiki/Autonomic_nervous_system» \o «Autonomic
nervous system» autonomic nervous system .

Parasympathetic innervation to the salivary glands is carried via
HYPERLINK «http://en.wikipedia.org/wiki/Cranial_nerve» \o «Cranial
nerve» cranial nerves . The HYPERLINK
«http://en.wikipedia.org/wiki/Parotid_gland» \o «Parotid gland» parotid
gland receives its parasympathetic input from the HYPERLINK
«http://en.wikipedia.org/wiki/Glossopharyngeal_nerve» \o
«Glossopharyngeal nerve» glossopharyngeal nerve (CN IX) via the
HYPERLINK «http://en.wikipedia.org/wiki/Otic_ganglion» \o «Otic
ganglion» otic ganglion , while the submandibular and sublingual glands
receive their parasympathetic input from the HYPERLINK
«http://en.wikipedia.org/wiki/Facial_nerve» \o «Facial nerve» facial
nerve (CN VII) via the HYPERLINK
«http://en.wikipedia.org/wiki/Submandibular_ganglion» \o «Submandibular
ganglion» submandibular ganglion .

Direct sympathetic innervation of the salivary glands takes place via
preganglionic nerves in the thoracic segments T1-T3 which synapse in the
superior cervical ganglion with postganglionic neurons that release
norepinephrine, which is then received by ?-adrenergic receptors on the
acinar and ductal cells of the salivary glands, leading to an increase
in cyclic adenosine monophosphate (cAMP) levels and the corresponding
increase of saliva secretion. Note that in this regard both
parasympathetic and sympathetic stimuli result in an increase in
salivary gland secretions. HYPERLINK
«http://en.wikipedia.org/wiki/Salivary_gland» \l «cite_note-1» \o «»
[2] The sympathetic nervous system also affects salivary gland
secretions indirectly by innervating the HYPERLINK
«http://en.wikipedia.org/wiki/Blood_vessel» \o «Blood vessel» blood
vessels that supply the glands.

Role in disease

HYPERLINK «http://en.wikipedia.org/wiki/Salivary_duct_calculus» \o
«Salivary duct calculus» Salivary duct calculus may cause blockage of
the ducts, causing pain and swelling of the gland.

Tumors of the salivary glands may occur.

Diagnostic investigation

A HYPERLINK «http://en.wikipedia.org/wiki/Sialogram» \o «Sialogram»
sialogram is a HYPERLINK «http://en.wikipedia.org/wiki/Radiocontrast»
\o «Radiocontrast» radiocontrast study of a HYPERLINK
«http://en.wikipedia.org/wiki/Salivary_duct» \o «Salivary duct»
salivary duct .

References

^ Cate, A.R. Ten. hi dude Oral Histology: development, structure, and
function. 5th ed. 1998. Page 3. ISBN 0-8151-2952-1.

^ Costanzo, L. (2006). Physiology, 3rd ed.. Saunders Elsevier. ISBN
10:1-4160-2320-8. 

External links

Salivary Gland Disorders at intelihealth.com

Illustration at merck.com

Illustration at .washington.edu

Photo at mgccc.cc.ms.us

plastic/371 at eMedicine — «Parotid Tumors, Benign»

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