Editing Small intestine (section)

===Development===
{{See also|Development of the digestive system}}
The small intestine develops from the [[midgut]] of the [[primitive gut tube]].<ref name=LARSENS2009>{{cite book|first1=Gary C. |last1=Schoenwolf |first2=Steven B. |last2=Bleyl |first3=Philip R. |last3=Brauer |first4=Philippa H. |last4=Francis-West |title=Larsen's human embryology|date=2009|publisher=Churchill Livingstone/Elsevier|location=Philadelphia |isbn=9780443068119 |chapter=Development of the Urogenital system |edition=4th |page=237}}</ref> By the fifth week of [[embryo]]logical life, the [[ileum]] begins to grow longer at a very fast rate, forming a U-shaped fold called the [[primary intestinal loop]]. The loop grows so fast in length that it outgrows the abdomen and protrudes through the [[Navel|umbilicus]]. By week 10, the loop retracts back into the abdomen. Between weeks six and ten the small intestine rotates anticlockwise, as viewed from the front of the embryo. It rotates a further 180 degrees after it has moved back into the abdomen. This process creates the twisted shape of the [[large intestine]].<ref name=LARSENS2009 />

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File:Sobo 1906 399.png|First stage of the development of the intestinal canal and the peritoneum, seen from the side (diagrammatic). From colon 1 the ascending and transverse colon will be formed and from colon 2 the descending and sigmoid colons and the rectum.
File:Sobo 1906 400.png|Second stage of development of the intestinal canal and peritoneum, seen from in front (diagrammatic). The liver has been removed and the two layers of the ventral mesogastrium (lesser omentum) have been cut. The vessels are represented in black and the peritoneum in the reddish tint.
File:Sobo 1906 401.png|Third state of the development of the intestinal canal and peritoneum, seen from in front (diagrammatic). The mode of preparation is the same as in [[:Image:Sobo 1906 400.png|Fig 400]]
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