Editing Mucous membrane (section)

==Structure==
The mucosa is composed of one or more layers of [[epithelial cells]] that secrete [[mucus]], and an underlying [[lamina propria]] of [[loose connective tissue]].<ref name="britan">{{cite encyclopedia|url=https://www.britannica.com/science/mucous-membrane|title=Mucous membrane|encyclopedia=Encyclopædia Britannica|access-date=1 August 2015}}</ref> The type of cells and type of mucus secreted vary from organ to organ and each can differ along a given tract.<ref name=Guyton2005>{{cite book|last1=Guyton|first1=Arthur C.|last2=Hall|first2=John E.|title=Textbook of Medical Physiology, 11th Edition|date=2006|isbn=9780721602400|oclc=56661571|publisher=Elsevier Saunders|location=Philadelphia}}</ref><ref>{{Cite book|last=Stuart-Low|first=William|url=https://books.google.com/books?id=nURIAAAAMAAJ|title=Mucous Membranes Normal & Abnormal Including Mucin & Malignancy|date=1905|publisher=Bailliére, Tindall & Cox|oclc=643969757|language=en}}</ref>

Mucous membranes line the digestive, respiratory and reproductive tracts and are the primary barrier between the external world and the interior of the body; in an adult human the total surface area of the mucosa is about 400 square meters while the surface area of the skin is about 2 square meters.<ref name="Sompayrac2012">{{cite book|last1=Sompayrac |first1=Lauren|url=https://books.google.com/books?id=oRsGFRKypn4C|title=How the Immune System Works, 4th Edition|date=30 January 2012|publisher=[[Wiley Publishing]]|isbn=9780470657294|location=Chichester, England|oclc=1036250938}}</ref>{{rp|1}} Along with providing a physical barrier, they also contain key parts of the immune system and serve as the interface between the body proper and the [[microbiome]].<ref name=Guyton2005/>{{rp|437}}

===Examples===
Some examples include:{{cn|date=July 2024}}
* [[Endometrium]]: the mucosa of the [[uterus]]
* [[Gastric mucosa]]
* [[Intestinal mucosa]]
* [[Nasal mucosa]]
* [[Olfactory mucosa]]
* [[Oral mucosa]]
* [[Preputial mucosa|Penile mucosa]]
* [[Respiratory mucosa]]
* [[Vaginal mucosa]]
* [[Frenulum of tongue]]
* [[Anal canal]]
* [[Conjunctiva]]

===Development===
Developmentally, the majority of mucous membranes are of [[endoderm]]al origin.<ref>{{Cite web|url=http://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-25-germ-layers-and-their-derivatives|title=Chapter 25. Germ Layers and Their Derivatives - Review of Medical Embryology Book - LifeMap Discovery|website=discovery.lifemapsc.com|access-date=2017-02-18|archive-url=https://web.archive.org/web/20170109185535/http://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-25-germ-layers-and-their-derivatives|archive-date=2017-01-09|url-status=dead}}</ref> Exceptions include the [[palate]], [[cheek]]s, floor of the [[Mouth#Mouth cavity|mouth]], [[gums]], [[lips]] and the portion of the [[anal canal]] below the [[pectinate line]], which are all [[ectoderm]]al in origin.<ref>{{Cite book|chapter-url=https://books.google.com/books?id=1caiau37J8kC&q=mucosa+is+of+ectodermal+origin&pg=PT81|title=Human Oral Mucosa: Development, Structure and Function|page=81|last1=Squier|first1=Christopher|last2=Brogden|first2=Kim|date=2010-12-29|publisher=John Wiley & Sons|isbn=9780470959732|language=en|chapter=Chapter 7, Development and aging of the oral mucosa}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=XQuqBAAAQBAJ&q=pectinate+line+embryology&pg=PA372|title=Larsen's Human Embryology|last1=Schoenwolf|first1=Gary C.|last2=Bleyl|first2=Steven B.|last3=Brauer|first3=Philip R.|last4=Francis-West|first4=Philippa H.|date=2014-12-01|publisher=Elsevier Health Sciences|isbn=9781455727919|pages=372|language=en}}</ref>