Muscular layer

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Muscular layer
Gray1134.png
Histological section of the ureter, showing the thick muscular layers surrounding the lumen.
Latin tunica muscularis

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.

Structure[edit]

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 and colon, 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:

References[edit]

This article incorporates text from a public domain edition of Gray's Anatomy.

External links[edit]