In the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

, the submucosa is the layer of dense irregular connective tissue
Dense irregular connective tissue
Dense irregular connective tissue has fibers that are not arranged in parallel bundles as in dense regular connective tissue.-Substances formed:...

 or loose connective tissue
Loose connective tissue
Loose connective tissue is extremely loose. It is a category of connective tissue which includes areolar tissue, reticular tissue, and adipose tissue....

 that supports the mucosa, as well as joins the mucosa to the bulk of underlying smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...

 (fibers running circularly within layer of longitudinal muscle).


Blood vessels, lymphatic vessels, and nerves (all supplying the mucosa) will run through here.

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
Muscularis mucosae
The lamina muscularis mucosae is the thin layer of smooth muscle found in most parts of the gastrointestinal tract, located outside the lamina propria mucosae and separating it from the submucosa....


The submucosa in endoscopy

Identification of the submucosa plays an important role in diagnostic and therapeutic endoscopy
Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an endoscope , an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ...

, where special fibre-optic cameras are used to perform procedures on the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

. Abnormalities of the submucosa, such as gastrointestinal stromal tumor
Gastrointestinal stromal tumor
A gastrointestinal stromal tumor is one of the most common mesenchymal tumors of the gastrointestinal tract...

s, usually show integrity of the mucosal surface
In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...


The submucosa is also identified in endoscopic ultrasound
Endoscopic ultrasound
Endoscopic ultrasound or echo-endoscopy is a medical procedure in endoscopy is combined with ultrasound to obtain images of the internal organs in the chest and abdomen. It can be used to visualize the wall of these organs, or to look at adjacent structures...

 to identify the depth of tumours and to identify other abnormalities. An injection of dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....

, saline
Saline (medicine)
In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...

, or epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...

 into the submucosa is imperative in the safe removal of certain polyps
Polyp (medicine)
A polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated. If no stalk is present, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, sinus, urinary bladder...


Endoscopic mucosal resection
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

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.

External links

- "Mammal, whole system (LM, Low)" - "Tissues, Layers, and Organs: transverse section of rat gut" - "Duodenum and Jejunum"
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