Circular Muscular Layer of Small intestine (Duodenum; Anterior)
Stratum musculare circulare intestini tenuis
Read moreStructure/Morphology
The cross-sectional microarchitecture of the small intestine demonstrates mucosa, submucosa, and muscular (inner circular and outer longitudinal) layers with a thin outer serosal covering.
The circular muscular layer forms the inner muscle fibers of the muscular layer and contains smooth muscle cells which are oriented roughly perpendicular to the long axis of the digestive canal.
Key Features/Anatomical Relations
The smooth muscle cells of the muscular layer are controlled by inputs from the vagus nerve and the myenteric nerve plexus. This plexus of enteric nerves sits between the inner circular and the outer longitudinal layers.
Function
The circular muscular contracts and reduce the diameter of the small intestine. Together with the outer longitudinal muscular layer, these fibers act to create rhythmic peristaltic contractions, mixing chyme and pushing contents distally.
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Small Intestine
The small intestine is a convoluted tubular organ, extending from the pylorus to the ileocecal valve, occupying the central and lower parts of the abdominal cavity.
