Muscular layer

Muscular layer or muscularis propria is a layer of muscle in the walls of hollow organs such as the stomach, esophagus, and intestines. It is responsible for gut movement such as peristalsis. The muscular layer is made up of two sub-layers of smooth muscle cells: the inner circular layer and the outer longitudinal layer.

Etymology

The term "muscular layer" is derived from the Latin musculus meaning "little mouse" and layer from the Old English leger meaning "bed, couch." The term "muscularis propria" is derived from the Latin musculus meaning "little mouse" and propria meaning "own, proper."

Structure

The muscular layer is composed of two sub-layers of smooth muscle cells: the inner circular layer and the outer longitudinal layer. The inner circular layer's muscle fibers run around the circumference of the organ and the outer longitudinal layer's fibers run along the length of the organ. The muscular layer is responsible for the movement of the organ, such as peristalsis in the gastrointestinal tract.

Function

The primary function of the muscular layer is to facilitate movement within the organ. This is achieved through the coordinated contraction and relaxation of the smooth muscle cells in the inner circular and outer longitudinal layers. In the gastrointestinal tract, this movement is known as peristalsis and is essential for the movement of food and waste through the system.

Clinical significance

Abnormalities or diseases of the muscular layer can lead to a variety of conditions. For example, Achalasia is a condition where the muscles in the lower part of the esophagus fail to relax, leading to difficulty swallowing. Hirschsprung's disease is a condition where the nerve cells in the muscular layer of the colon are absent, leading to severe constipation and intestinal obstruction.

See also

• Smooth muscle tissue
• Peristalsis
• Gastrointestinal tract

Muscular_layer

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  Gray's Anatomy illustration of the muscular layer