|This article does not cite any references or sources. (March 2013)|
Serosa or Adventitia
|Endoscopy and radial endoscopic ultrasound images of submucosal tumour in mid-esophagus. The submucosa is seen as a dark ring on the ultrasound image.|
In the gastrointestinal tract, the submucosa is the layer of dense irregular connective tissue or loose connective tissue that supports the mucosa, as well as joins the mucosa to the bulk of overlying smooth muscle (fibers running circularly within layer of longitudinal muscle).
Tiny parasympathetic ganglia are scattered around forming the submucosal plexus (or "Meissner's plexus") where preganglionic parasympathetic neurons synapse with postganglionic nerve fibers that supply the muscularis mucosae. Histologically, the wall of the alimentary canal shows four distinct layers (from the lumen moving out): mucosa, submucosa, muscularis externa, and a serosa or adventitia.
The submucosa in endoscopy
Identification of the submucosa plays an important role in diagnostic and therapeutic endoscopy, where special fibre-optic cameras are used to perform procedures on the gastrointestinal tract. Abnormalities of the submucosa, such as gastrointestinal stromal tumors, usually show integrity of the mucosal surface.
The submucosa is also identified in endoscopic ultrasound to identify the depth of tumours and to identify other abnormalities. An injection of dye, saline, or epinephrine into the submucosa is imperative in the safe removal of certain polyps.
Endoscopic mucosal resection involves removal of the mucosal layer, and in order to be done safely, a submucosal injection of dye is performed to ensure integrity at the beginning of the procedure.
Section of the human esophagus. Moderately magnified.
- Organology at UC Davis Digestive/mammal/system1/system5 - "Mammal, whole system (LM, Low)"
- submucosa at eMedicine Dictionary
- BU Histology Learning System: 00102loa - "Tissues, Layers, and Organs: transverse section of rat gut"
- Physiology at MCG 6/6ch1/s6ch1_9
- Histology at OU 55_11
- Anatomy Atlases - Microscopic Anatomy, plate 10.193 - "Duodenum and Jejunum"
- Histology at edteched.uottawa.ca