Editing Small intestine (section)

===Immunological===
The small intestine supports the body's [[immune system]].<ref>{{cite web|url=http://www.massgeneral.org/about/pressrelease.aspx?id=1533|title=Intestinal immune cells play an unexpected role in immune surveillance of the bloodstream|publisher=Massachusetts General Hospital|date=13 December 2012|access-date=28 August 2013|archive-date=16 October 2018|archive-url=https://web.archive.org/web/20181016130005/https://www.massgeneral.org/about/pressrelease.aspx?id=1533|url-status=dead}}</ref>  The presence of [[gut flora]] appears to contribute positively to the host's immune system.
[[Peyer's patch]]es, located within the ileum of the small intestine, are an important part of the digestive tract's local immune system. They are part of the lymphatic system, and provide a site for antigens from potentially harmful bacteria or other microorganisms in the digestive tract to be sampled, and subsequently presented to the immune system.<ref>{{cite journal|last1=Canny|first1=G. O.|last2=McCormick|first2=B. A.|title=Bacteria in the Intestine, Helpful Residents or Enemies from Within?|journal=Infection and Immunity|volume=76|issue=8|year=2008|pages=3360–3373|issn=0019-9567|doi=10.1128/IAI.00187-08|pmc=2493210|pmid=18474643|citeseerx=10.1.1.596.7265}}</ref>