Submandibular gland


Submandibular gland
Submandibular gland
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Salivary glands:
1 - parotid gland,
2 - submandibular gland,
3 - sublingual gland
Latin glandula submandibularis
Artery glandular branches of facial artery
Nerve submandibular ganglion
MeSH Submandibular+Gland

The paired submandibular glands (submaxillary glands) are salivary glands located beneath the floor of the mouth. In humans, they account for 70% of the salivary volume and weigh about 15 grams. Unstimulated (at rest) in humans, the percentage contribution to whole saliva; ~25% Parotid, Submandibular and Sublingual ~ 67% and ~8% minor mucous glands. During stimulated secretion the parotid gland produces majority of the saliva.

Contents

Anatomy

Lying superior to the digastric muscles, each submandibular gland is divided into superficial and deep lobes, which are separated by the mylohyoid muscle:

  • The deep portion is the smaller portion. The mylohyoid muscle runs below it.
  • The superficial portion comprises most of the gland.

Secretions are delivered into the Wharton's ducts on the deep 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 caruncles on either side of the lingual frenulum along with the major sublingual duct (Bartholin).

Histology

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 adenomeres, 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 cells, 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 glands, 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 glands. 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 viscous cells of the submandibular gland have distinct functions. The mucous cells are the most active and therefore the major product of the submandibular glands is saliva. In particular, the serous cells produce salivary amylase, which aids in the breakdown of starches in the mouth. Mucous cells secrete mucin which aids in the lubrication of the food bolus as it travels through the esophagus.

The submandibular gland's highly active acini account for approximately 70% of salivary volume. The parotid and sublingual glands account for the remaining 30%.

Innervation

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 mucous 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

References

  • Douglas F. Paulsen (2000). Histology and cell biology (4th edition ed.). Stamford, Conn: Lange Medical Books/McGraw Hill. ISBN 0-8385-0593-7. 
  • A. R. Ten Cate (1998). Oral Histology: Development, Structure, and Function (5th edition ed.). Saint Louis: Mosby-Year Book. 

External links


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Look at other dictionaries:

  • Submandibular gland — The second largest of the three major salivary glands. It is located deep to the mandible (jaw bone). * * * submandibular gland n a salivary gland inside of and near the lower edge of the mandible on each side and discharging by Wharton s duct… …   Medical dictionary

  • submandibular gland — noun a salivary gland inside the lower jaw on either side that produces most of the nocturnal saliva; discharges saliva into the mouth under the tongue • Syn: ↑submaxillary gland, ↑submaxillary salivary gland, ↑submandibular salivary gland,… …   Useful english dictionary

  • submandibular gland — /sub man dib yeuh leuhr/ either of a pair of salivary glands located one on each side of and beneath the lower jaw. Also called submaxillary gland. [SUB + MANDIBULAR] * * * …   Universalium

  • submandibular gland — (also submaxillary gland) noun Anatomy either of a pair of salivary glands situated below the parotid glands …   English new terms dictionary

  • submandibular gland — submaxillary gland one of a pair of salivary glands situated below the parotid glands. Their ducts (Wharton s ducts) open in two papillae under the tongue, on either side of the frenulum …   The new mediacal dictionary

  • Железа Поднижнечелюстная (Submandibular Gland, Submaxillary Gland) — парная слюнная железа, расположенная в поднижнечелюстном треугольнике. Выводной проток железы (вартонов проток (Wharton s ducts)) открывается на сосочке, расположенном под языком с обеих сторон от уздечки. Источник: Медицинский словарь …   Медицинские термины

  • Submandibular triangle — Submandibular triangle …   Wikipedia

  • submandibular ganglion — n an autonomic ganglion that is situated on the hyoglossus muscle above the deep part of the submandibular gland, receives preganglionic fibers from the facial nerve by way of the chorda tympani, and sends postganglionic fibers to the… …   Medical dictionary

  • Submandibular ganglion — Infobox Nerve Name = PAGENAME Latin = ganglion submandibulare GraySubject = 200 GrayPage = 898 Caption = Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion. (Submandibular ganglion visible at bottom left, but not… …   Wikipedia

  • Submandibular duct — Infobox Anatomy Name = PAGENAME Latin = ductus submaxillaris GraySubject = 241 GrayPage = 1135 Caption = Dissection, showing salivary glands of right side. (Labeled as submaxillary duct , but is identified as submandibular duct in newer sources.) …   Wikipedia


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