The lamina muscularis mucosae (or muscularis mucosae) is a thin layer (
lamina
Lamina may refer to:
Science and technology
* Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics
* Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...
) of
muscle of the
gastrointestinal tract, located outside the
lamina propria, and separating it from the
submucosa. It is present in a continuous fashion from the
esophagus
The esophagus ( American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to ...
to the upper
rectum (the exact nomenclature of the rectum's muscle layers is still being debated). A discontinuous muscularis mucosae–like muscle layer is present in the
urinary tract
The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, c ...
, from the
renal pelvis to the
bladder
The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...
; as it is discontinuous, it should not be regarded as a true muscularis mucosae.
In the
gastrointestinal tract, the term ''mucosa'' or ''
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
'' refers to the combination of
epithelium, lamina propria, and (where it occurs) muscularis mucosae.
[H.G. Burkitt et al., ''Wheater's Functional Histology, 3rd ed.''] The etymology suggests this, since the Latin names translate to "the mucosa's own special layer" (''lamina propria mucosae'') and "muscular layer of the mucosa" (''lamina muscularis mucosae'').
The muscularis mucosae is composed of several thin layers of
smooth muscle fibers oriented in different ways which keep the mucosal surface and underlying
glands in a constant state of gentle agitation to expel contents of glandular
crypts
A crypt (from Latin '' crypta'' "vault") is a stone chamber beneath the floor of a church or other building. It typically contains coffins, sarcophagi, or religious relics.
Originally, crypts were typically found below the main apse of a chu ...
and enhance contact between epithelium and the contents of the
lumen.
Additional images
Image:Gray1033.png, Section of the human esophagus
The esophagus ( American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to ...
. Moderately magnified.
Image:Gray1053.png, Section of mucous membrane of human stomach, near the cardiac orifice.
Image:Gray1082.png, Section of mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
of human rectum. X 60.
Image:Illu stomach layers.jpg, Layers of stomach wall
Image:Gut wall.svg, General structure of the gut wall showing the Muscularis mucosa.
References
Stacey E. Mills — Histology for Pathologists: 3rd (third) Edition, page 670.
External links
*
* — "Lung"
*
* - "Mammal, whole system (LM, Low)"
*
Membrane biology
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