Muscularis externa
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
Muscularis externa
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
- Inner circular layer
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
- Outer longitudinal layer
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
Myenteric plexus
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
Submucosal plexus >
A small ganglion of the submucosal plexus is visible adjacent to the inner circular layer of the muscularis externa externa.
Serosa
The muscularis externa of the small intestine, seen here in cross section (left) and longitudinal section (right), is composed of inner circular and outer longitudinal layers of smooth muscle, similar to other regions of the digestive tract. Located between the layers is the myenteric (Auerbach’s) plexus, a component of the enteric nervous system that controls contraction of the smooth muscle. Contractions of the longitudinal layer muscle provides propulsion of the luminal contents (peristalsis); contraction of the inner circular layer divides and mixes the luminal contents (segmentation). 200x
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