Submandibular gland
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2008-06-17T06:33:46Z
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{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = glandula submandibularis |
GraySubject = |
GrayPage = |
Image = Illu_quiz_hn_02.jpg |
Caption = [[Salivary glands]]: #1 is [[parotid gland]], #2 is [[submandibular gland]], #3 is [[sublingual gland]] |
Image2 = |
Caption2 = |
Precursor = |
System = |
Artery = [[glandular branches of facial artery]] |
Vein = |
Nerve = [[submandibular ganglion]] |
Lymph = |
MeshName = Submandibular+Gland |
MeshNumber = A03.556.500.760.812 |
DorlandsPre = g_06 |
DorlandsSuf = 12392708 |
}}
The paired '''submandibular glands''' (or '''submaxillary glands''') are [[salivary gland]]s located beneath the floor of the mouth. In humans, they account for 70% of the [[saliva]]ry volume and weigh about 15 grams.
==Anatomy==
Lying superior to the [[digastric muscle]]s, each submandibular gland is divided into superficial and deep lobes, which are separated by the [[mylohyoid muscle]].
* The superficial portion is larger. The mylohyoid muscle is deep to it.
* The deep portion is smaller.
Secretions are delivered into [[Wharton's duct]]s on the superficial portion after which they hook around the posterior edge of the mylohyoid muscle and proceed on the superior surface laterally. The ducts are then crossed by the [[lingual nerve]], and ultimately drain into the [[Sublingual caruncle]]s on either side of the [[lingual frenulum]] along with the Major [[Sublingual duct]] (Bartholin).
==Histology==
[[Image:Gray1026.png|thumb|Human submaxillary gland. At the right is a group of mucous alveoli, at the left a group of serous alveoli.]]
Lobes contain smaller lobules, which contain [[adenomere]]s, the secretory units of the gland. Each adenomere contains one or more acini, or alveoli, which are small clusters of cells that secrete their products into a duct. The acini of each adenomere are composed of either [[serous]] or [[mucous cell]]s, with serous adenomeres predominating. Some mucous adenomeres may also be capped with a [[serous demilune]], a layer of [[lysozyme]]-secreting serous cells resembling a half moon.
Like other [[exocrine gland]]s, the submandibular gland can be classified by the microscopic anatomy of its secretory cells and how they are arranged. Because the glands are branched, and because the tubules forming the branches contain secretory cells, submandibular glands are classified as [[branched tubuloacinar gland]]s. Further, because the secretory cells are of both serous and mucous types, the submandibular gland is a [[mixed gland]], though it is mostly serous.
==Functions==
The secretory cells of the submandibular gland have distinct functions. In particular, the serous cells produce salivary [[amylase]], which aids in the breakdown of [[starch]]es in the mouth. Mucous cells secrete [[mucin]] which aids in the lubrication of the food [[Bolus (digestion)|bolus]] as it travels through the [[esophagus]]. The mucous cells are the most active and therefore the major product of the submandibular glands is [[viscous]] saliva.
The submandibular gland's highly active acini account for approximately 70% of salivary volume. The [[parotid gland|parotid]] and [[sublingual gland]]s account for the remaining 30%.
==Innervation==
[[Image:Gray842.png|thumb|Parasympathetic and Sympathetic connections of the submaxillary and superior cervical ganglia.]]
Their secretions, like the secretions of other salivary glands, are regulated ''directly'' by the [[parasympathetic nervous system]] and ''indirectly'' by the [[sympathetic nervous system]].
* ''Parasympathetic'' innervation to the submandibular glands is provided by the [[superior salivatory nucleus]] via the [[chorda tympani]], a branch of the [[facial nerve]] that synapses in the [[submandibular ganglion]] after which it follows the [[Lingual nerve]] leaving this nerve as it approaches the gland. Increased parasympathetic activity promotes the secretion of saliva.
* The sympathetic nervous system regulates submandibular secretions through [[vasoconstriction]] of the arteries that supply it. Increased sympathetic activity reduces glandular bloodflow, thereby decreasing salivary secretions and producing an [[enzyme]] rich [[serous]] saliva.
==Pathology==
The submandibular gland accounts for 80% of all [[salivary duct calculi]], possibly due to the different nature of the saliva that it produces and that its duct is up-sloping.
==Additional images==
<gallery>
Image:Gray177.png|Mandible. Inner surface. Side view.
Image:Gray778.png|Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion.
Image:Digestive_system_diagram_en.svg|Digestive system
image:WVSOM Submandibular Gland.JPG|Mucus cell are identifiable by the lack of color in their cytoplasm, while serosal cells have a basophilic color.
</gallery>
==References==
*{{cite book | author = Douglas F. Paulsen | title = Histology and cell biology | publisher = Lange Medical Books/McGraw Hill | location = Stamford, Conn | year = 2000 | edition = 4th edition | id = ISBN 0-8385-0593-7}}
*{{cite book | author = A. R. Ten Cate | title = Oral Histology: Development, Structure, and Function | publisher = Mosby-Year Book | location = Saint Louis | year = 1998 | edition = 5th edition }}
==External links==
* [http://www.usc.edu/hsc/dental/ohisto/Cards/sal/34_tns.html Histology at usc.edu]
* {{eMedicineDictionary|submandibular+gland}}
* {{SUNYAnatomyLabs|25|10|01|09}} - "Anterior Triangle of the Neck: Nerves and Vessels of the Carotid Triangle"
* {{SUNYAnatomyLabs|34|09|01|02}} - "Oral Cavity: The Submandibular Gland and Duct"
* {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|VII}})
{{Head and neck general}}
[[Category:Digestive system]]
[[Category:Mouth]]
[[ar:غدة تحت الفك السفلي]]
[[de:Glandula submandibularis]]
[[fr:Submandibulaire]]
[[is:Kjálkabarðskirtill]]
[[it:Ghiandola sottomandibolare]]
[[la:Glandula submandibularis]]
[[pl:Ślinianka podżuchwowa]]
[[pt:Glândula submandibular]]
[[sr:Подвилична жлезда]]