“Muscular layer”的意思、由来-开放百科全书

词条

Muscular layer

释义

Structure
References
External links

{{Infobox anatomy
| Name = Muscular layer
| Latin = tunica muscularis
| Greek =
| Image = Gray1134.png
| Caption = Histological section of the ureter, showing the thick muscular layers surrounding the lumen.
| Width =
| Image2 =
| Caption2 =
| Precursor =
| System =
| Artery =
| Vein =
| Nerve =
| Lymph =
}}{{Gastrointestinal wall series}}

The muscular layer (muscular coat, muscular fibers, muscularis propria, muscularis externa) is a region of muscle in many organs in the vertebrate body, adjacent to the submucosa. It is responsible for gut movement such as peristalsis. The Latin, tunica muscularis, may also be used.

Structure

It usually has two 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 muscular layer.
In the upper esophagus, part of the externa is skeletal muscle, rather than smooth muscle.
In the vas deferens of the spermatic cord, there are three layers: inner longitudinal, middle circular, and outer longitudinal.
In the ureter the smooth muscle orientation is opposite that of the GI tract. There is an inner longitudinal and an outer circular layer.

The inner layer of the muscularis externa forms a sphincter at two locations of the gastrointestinal tract:

in the pylorus of the stomach, it forms the pyloric sphincter
in the anal canal, it forms the internal anal sphincter

References

External links

{{BiowebUW|APLab/Table_of_Contents/Lab_12/Colon_1/Colon_1e/colon_1e.html|Muscularis externa of the colon}}
{{BiowebUW|zoolab/Table_of_Contents/Lab-1b/Cross_section_of_the_small_int/Smooth_muscle_layers/smooth_muscle_layers.htm|Smooth muscle layers of the gut}}
{{UIUCHistologySubject|23}}
{{BUHistology|11601ooa}} — "Muscle Tissue: smooth muscle, muscularis externa"

1 : Membrane biology

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