Section of the human esophagus. Moderately magnified. The section is transverse and from near the middle of the gullet.
a. Fibrous covering.
b. Divided fibers of longitudinal muscular coat.
c. Transverse muscular fibers.
d. Submucous or areolar layer.
e. Muscularis mucosae.
f. Mucous membrane, with vessels and part of a lymphoid nodule.
g. Stratified epithelial lining.
h. Mucous gland.
i. Gland duct.
m’. Striated muscular fibers cut across.
There are two types:
- Esophageal glands proper- located in the submucosa and secrete acid mucin for lubrication
- Esophageal cardiac glands- in the lamina propria and secrete neutral mucus that protects the esophagus from acidic gastric juices.
Each opens upon the surface by a long excretory duct.
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, Neritimorpha and Neomphalina.
The size of oesophageal gland of scaly-foot gastropod 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.
- Chen, C.; Copley, J.; Linse, K.; Rogers, A.; Sigwart, J. (2015). "The heart of a dragon: 3D anatomical reconstruction of the 'scaly-foot gastropod' (Mollusca: Gastropoda: Neomphalina) reveals its extraordinary circulatory system". Frontiers in Zoology. 12: 13. doi:10.1186/s12983-015-0105-1.
- Chen C., Linse K., Roterman C. N., Copley J. T. & Rogers A. D. (2015). "A new genus of large hydrothermal vent‐endemic gastropod (Neomphalina: Peltospiridae)". Zoological Journal of the Linnean Society 175(2), 319-335. doi:10.1111/zoj.12279.
- Histology image: 49_07 at the University of Oklahoma Health Sciences Center
- Histology image: 10802loa – Histology Learning System at Boston University
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