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The esophageal glands are glands that are part of the digestive system of various animals, including humans.


In humans

Esophageal glands in humans are a part of a human digestive system. They are a small compound racemose exocrine glands of the mucous type. There are two types: * Esophageal glands proper- mucous glands located in the submucosa. They are compound tubulo-alveolar glands. Some serous cells are present. These glands are more numerous in the upper third of the esophagus. They secrete acid mucin for lubrication. * Esophageal cardiac glands- mucous glands located near the cardiac orifice (esophago-gastric junction) in the lamina propria mucosae. They secrete neutral mucin that protects the esophagus from acidic gastric juices. They are simple tubular or branched tubular glands. * There are also mucous glands present at the pharyngo-esophageal junction in the lamina propria mucosae. These are simple tubular or branched tubular glands. Each opens upon the surface by a long excretory duct.


In monoplacophorans

Oesophageal gland is enlarged in large
monoplacophora Monoplacophora , meaning "bearing one plate", is a polyphyletic superclass of molluscs with a cap-like shell inhabiting deep sea environments . Extant representatives were not recognized as such until 1952; previously they were known only from ...
n species.


In gastropods

Oesophageal gland or oesophageal pouch is a part of the digestive system of some gastropods. Oesophageal gland or pouch is a common feature in so-called basal gastropod clades, including Patelloidea, Vetigastropoda,
Cocculiniformia The Cocculinoidea is a superfamily of deepwater limpets (marine gastropods), the only superfamily in the order Cocculinida , one of the main orders of gastropods according to the taxonomy as set up by ( Bouchet & Rocroi, 2005). The clade Coccilin ...
, Neritimorpha and Neomphalina. The size of oesophageal gland of
scaly-foot gastropod ''Chrysomallon squamiferum'', commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a species of deep-sea hydrothermal-vent snail, a marine gastropod mollusc in the family Peltospiridae. This vent- ...
''Chrysomallon squamiferum'' (family Peltospiridae within Neomphalina) is about two orders of magnitude over the usual size. The scaly-foot gastropod houses endosymbiotic Bacteria in the oesophageal gland. ''Chrysomallon squamiferum'' was thought to be the only species of Peltospiridae, that has enlarged oesophageal gland, but later it was shown that both species '' Gigantopelta'' has the oesophageal gland also enlarged. In other peltospirids, the posterior portion of the oesophagus forms a pair of blind mid-oesophageal pouches or gutters extending only to the anterior end of the foot ('' Rhynchopelta'', '' Peltospira'', '' Nodopelta'', '' Echinopelta'', '' Pachydermia''). The same situation is in '' Melanodrymia'' within the family Melanodrymiidae. Bathyphytophilidae and Lepetellidae are also known to have enlarged oesophageal pouches, however, though not to the extent of ''Chrysomallon''. Both are known to house endosymbiotic bacteria, in the case of bathyphytophilids most likely also in the oesophageal glands but in the lepetellids the endosymbionts are spread in the haemocoel.


References

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External links

* * {{Authority control Digestive system Glands