Muscularis Externa

Information about Muscularis Externa



LAYERS: serosa longitudinal muscle myenteric plexus circular muscle submucosal plexus submucosal mucosal

Transverse section of ureter.
Latin	tunica muscularis
Dorlands/Elsevier	t_22/12832129

The muscular coat (or muscular layer, or muscular fibers, or muscularis propria, or muscularis externa) is a region of muscle in many organs in the vertebrate body, adjacent to the mucous membrane. It is responsible for gut movement such as peristalsis.

It usually has two distinct layers of smooth muscle:

inner and "circular"
outer and "longitudinal"

However, there are some exceptions to this pattern.

In the stomach, there are three layers to the muscularis externa.
In the upper esophagus, part of the externa is skeletal muscle, rather than smooth muscle.

The inner layer of the muscularis externa forms a sphincter at two locations of the alimentary canal:

in the pyloric stomach, it forms the pyloric sphincter
in the anal canal, it forms the anal sphincter

Additional images

Wall of the ureter.	Layers of stomach wall.	Section of the human esophagus. Moderately magnified.	Section of duodenum of cat. X 60.
Vertical section of bladder wall.

External links

muscular+layer at eMedicine Dictionary
Histology at nhmccd.edu
Bioweb at UWLAX Muscularis externa of the colon
Bioweb at UWLAX Smooth muscle layers of the gut
Histology at OU 52_05 - "Duodenum"
Organology at UC Davis Digestive/mammal/system1/system7 - "Mammal, whole system (LM, Low)"
UIUC Histology Subject 23
Histology at BU 11601ooa - "Muscle Tissue: smooth muscle, muscularis externa"
Histology at BU 10802loa - "Digestive System: Alimentary Canal - esophagus "

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

• • [ e] tissue layers
mesothelium, serosa/adventitia, muscularis externa (outer & inner), submucosa, mucosa (muscularis mucosa, lamina propria, epithelium), lumen

In anatomy, a serous membrane, or serosa, is a smooth membrane consisting of a thin layer of cells which excrete a fluid, known as serous fluid. Serous membranes line and enclose several body cavities, known as serous cavities, where they secrete a lubricating fluid which
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Part of the enteric nervous system, Auerbach's plexus (or myenteric plexus) exists between the longitudinal and circular layers of muscularis externa in the gastrointestinal tract and provides motor innervation to both layers and secretomotor innervation to the mucosa.
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plexus of the submucosa (Meissner's plexus, Submucous plexus, submucosal plexus) is derived, and is formed by branches which have perforated the circular muscular fibers.
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In the gastrointestinal tract, the submucosa is the layer of loose connective tissue that supports the mucosa, as well as joins the mucosa to the bulk of underlying smooth muscle (fibers running circularly within layer of longitudinal muscle).
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The mucous membranes (or mucosae; singular: mucosa) are linings of mostly endodermal origin, covered in epithelium, and are involved in absorption and secretion. They line various body cavities that are exposed to the external environment and internal organs.
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In human anatomy, the ureters are the ducts that carry urine from the kidneys to the urinary bladder, passing anterior to the psoas major. The ureters are muscular tubes that can propel urine along by the motions of peristalsis. In the adult, the ureters are usually 25-30cm long.
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Latin}}}
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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MUSCLE (multiple sequence comparison by log-expectation) is public domain, multiple sequence alignment software for protein and nucleotide sequences.
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Peristalsis is the rhythmic contraction of smooth muscles to propel contents through the digestive tract. The word is derived from New Latin and comes from the Greek peristaltikos, peristaltic, from peristellein, "to wrap around," and stellein
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Smooth muscle is a type of non-striated muscle, found within the "walls" of hollow organs and elsewhere like the bladder and abdominal cavity, the uterus, male and female reproductive tracts, the gastrointestinal tract, the respiratory tract, the vasculature, the skin and the
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The esophagus (also spelled oesophagus/œsophagus, Greek οἰσοφάγος), or gullet
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Skeletal muscle is a type of striated muscle, usually attached to the skeleton. Skeletal muscles are used to create movement, by applying force to bones and joints; via contraction.
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A sphincter is a structure, usually a circular muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning.
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gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste.
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Not to be confused with Pillory.

The pylorus (from Greek πυλωρος = "gate guard") is the region of the stomach that connects to the duodenum.
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Not to be confused with Pillory.

The pylorus (from Greek πυλωρος = "gate guard") is the region of the stomach that connects to the duodenum.
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The anal canal is the terminal part of the large intestine.

It is situated between the rectum and anus, below the level of the pelvic diaphragm. It lies in the anal triangle of perineum in between the right and left ischiorectal fossae.
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anus (from Latin ānus "ring, anus") is the external opening of the rectum. Closure is controlled by sphincter muscles. Feces are expelled from the body through the anus during the act of defecation, which is the primary function of the anus.
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The esophagus (also spelled oesophagus/œsophagus, Greek οἰσοφάγος), or gullet
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In anatomy of the digestive system, the duodenum is a hollow jointed tube about 25-30 cm long connecting the stomach to the jejunum. It is the first and shortest part of the small intestine and it is where most chemical digestion takes place.
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eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely, two medical doctors. It was sold to WebMD in January 2006.
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University of Wisconsin–La Crosse (also known as UW–La Crosse, Wisconsin-La Crosse, or UW-L) is a public university located in La Crosse, Wisconsin, USA.
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University of Oklahoma, abbreviated OU, is a coeducational public research university located in the U.S. state of Oklahoma. Founded in 1890, it existed in Oklahoma Territory near Indian Territory 17 years before the two became the state of Oklahoma.
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University of California, Davis, commonly known as UC Davis, is one of the ten campuses of the University of California, and was established as the University Farm in 1905.
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The College of Medicine at Urbana-Champaign is a graduate school at the University of Illinois at Urbana-Champaign.The UIC College of Medicine at Urbana-Champaign is located at the original campus of the University (with 42,000 students, undergraduate and graduate) and offers a
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