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{{ | {{short description|Pouch in the large intestine}} | ||
{{ | {{Redirect|Caecum|the genus of sea snails|Caecum (genus)|other taxonomic uses|List of Latin and Greek words commonly used in systematic names}} | ||
{{ | {{Distinguish|sacrum}} | ||
{{Infobox anatomy | {{Infobox anatomy | ||
| Name = Cecum | | Name = Cecum | ||
| Latin = caecum | | Latin = caecum | ||
| Image = Tractus intestinalis cecum.svg | | Image = Tractus intestinalis cecum.svg | ||
| Caption = The cecum, here in red, lies at the start of the large | | Caption = The cecum, here in red, lies at the start of the large intestine, which is shown with the rest of the human gastrointestinal tract in this image. | ||
| Width = | | Width = | ||
| Image2 = Gray1043.png | | Image2 = Gray1043.png | ||
| Line 16: | Line 16: | ||
| Nerve = | | Nerve = | ||
| Lymph = | | Lymph = | ||
|PartOf=[[Large intestine]]|Location=Lower right part of the abdomen | | PartOf = [[Large intestine]] | ||
| Location = Lower right part of the abdomen | |||
}} | |||
The '''cecum''' ({{small|[[British English|UK]]:}} '''caecum''', {{small|pronounced}} {{IPAc-en|ˈ|s|iː|k|əm}}; plural '''ceca''' or {{small|[[British English|UK]]:}} '''caeca''', {{small|pronounced}} {{IPAc-en|ˈ|s|iː|k|ə}}) is a pouch within the [[peritoneum]] that is considered to be the beginning of the [[large intestine]].<ref name="Stedman 2000 p. ">{{cite book | last=Stedman | first=Thomas | title=Stedman's medical dictionary | publisher=Lippincott Williams & Wilkins | publication-place=Philadelphia | year=2000 | isbn=978-0-683-40007-6 | oclc=42772946 | page=915 | quote='''large i[ntestine]''', the portion of the digestive tube extending from the ileocecal valve to the anus; it comprises the cecum, colon, rectum, and anal canal }}</ref> It is typically located on the right side of the body (the same side of the body as the [[appendix (anatomy)|appendix]], to which it is joined). The term stems from the [[Latin]] ''[[wikt:caecus|caecus]]'', meaning "[[blindness|blind]]". | The '''cecum''' ({{small|[[British English|UK]]:}} '''caecum''', {{small|pronounced}} {{IPAc-en|ˈ|s|iː|k|əm}}; plural '''ceca''' or {{small|[[British English|UK]]:}} '''caeca''', {{small|pronounced}} {{IPAc-en|ˈ|s|iː|k|ə}}) is a pouch within the [[peritoneum]] that is considered to be the beginning of the [[large intestine]].<ref name="Stedman 2000 p. ">{{cite book |last=Stedman |first=Thomas |title=Stedman's medical dictionary |publisher=Lippincott Williams & Wilkins |publication-place=Philadelphia |year=2000 |isbn=978-0-683-40007-6 |oclc=42772946 |page=915 |quote='''large i[ntestine]''', the portion of the digestive tube extending from the ileocecal valve to the anus; it comprises the cecum, colon, rectum, and anal canal}}</ref> It is typically located on the right side of the body (the same side of the body as the [[appendix (anatomy)|appendix]], to which it is joined). The term stems from the [[Latin]] ''[[wikt:caecus|caecus]]'', meaning "[[blindness|blind]]". | ||
It receives [[chyme]] from the [[ileum]], and connects to the [[ascending colon]] of the [[large intestine]]. It is separated from the ileum by the [[ileocecal valve]] (ICV), also called Bauhin's valve. It is also separated from the [[Large intestine#Structure|colon]] by the cecocolic junction. While the cecum is usually intraperitoneal, the ascending colon is [[Retroperitoneal space|retroperitoneal]].<ref>{{cite web|url= | It receives [[chyme]] from the [[ileum]], and connects to the [[ascending colon]] of the [[large intestine]]. It is separated from the ileum by the [[ileocecal valve]] (ICV), also called Bauhin's valve. It is also separated from the [[Large intestine#Structure|colon]] by the cecocolic junction. While the cecum is usually intraperitoneal, the ascending colon is [[Retroperitoneal space|retroperitoneal]].<ref>{{cite web |url=https://download.videohelp.com/vitualis/med/large_intestine.htm |title=The Large Intestine |publisher=VideoHelp.com}}</ref> | ||
In [[herbivore]]s, the cecum stores food material where bacteria are able to break down the [[cellulose]]. In humans, the cecum is involved in absorption of [[ | In [[herbivore]]s, the cecum stores food material where bacteria are able to break down the [[cellulose]]. In humans, the cecum is involved in absorption of [[salt (chemistry)|salts]] and [[electrolyte]]s and lubricates the solid waste that passes into the large intestine.<ref>{{Cite web |url=https://www.sciencing.com/functions-cecum-6809336/ |title=What Are the Functions of the Cecum?}}</ref> | ||
==Structure== | ==Structure== | ||
| Line 32: | Line 34: | ||
==History== | ==History== | ||
===Etymology=== | ===Etymology=== | ||
The term ''cecum'' comes from Latin ''(intestinum) caecum'', literally 'blind intestine', in the sense 'blind gut' or '[[cul de sac]]'.<ref>{{Cite web |title= | The term ''cecum'' comes from Latin ''(intestinum) caecum'', literally 'blind intestine', in the sense 'blind gut' or '[[cul de sac]]'.<ref>{{Cite web |title=Caecum - Etymology, Origin, and Meaning |url=https://www.etymonline.com/word/caecum |access-date=2022-05-27 |website=etymonline.com |language=en}}</ref> It is a direct translation from Ancient Greek {{lang|grc|τυφλὸν}} ({{lang|grc|ἔντερον}}) {{transliteration|grc|typhlòn}} ({{transliteration|grc|énteron}}). Thus the inflammation of the cecum is called typhlitis. | ||
In [[dissection]]s by the [[Ancient Greece|Greek]] [[Greek philosophy|philosophers]], the connection between the [[ileum]] of the [[small intestine]] and the cecum was not fully understood. Most of the studies of the [[Gastrointestinal tract|digestive tract]] were done on animals and the results were compared to human [[human anatomy|structures]].<ref>{{Cite web |title=Ileum |url=https://www.kenhub.com/en/library/anatomy/the-ileum |access-date=2022-06-18 |website=Kenhub |language=en}}</ref> | In [[dissection]]s by the [[Ancient Greece|Greek]] [[Greek philosophy|philosophers]], the connection between the [[ileum]] of the [[small intestine]] and the cecum was not fully understood. Most of the studies of the [[Gastrointestinal tract|digestive tract]] were done on animals and the results were compared to human [[human anatomy|structures]].<ref>{{Cite web |title=Ileum |url=https://www.kenhub.com/en/library/anatomy/the-ileum |access-date=2022-06-18 |website=Kenhub |language=en}}</ref> | ||
The junction between the small intestine and the colon, called the [[ileocecal valve]], is so small in some animals that it was not considered to be a connection between the small and large intestines. During a dissection, the colon could be traced from the [[rectum]], to the [[sigmoid colon]], through the [[descending colon|descending]], [[transverse colon|transverse]], and [[ascending colon|ascending]] sections. The cecum is an end point for the colon with a dead-end portion terminating with the [[appendix (anatomy)|appendix]].<ref>{{cite web|last1=Taylor|first1=Tim|title=Anatomy and Physiology Instructor|url= | The junction between the small intestine and the colon, called the [[ileocecal valve]], is so small in some animals that it was not considered to be a connection between the small and large intestines. During a dissection, the colon could be traced from the [[rectum]], to the [[sigmoid colon]], through the [[descending colon|descending]], [[transverse colon|transverse]], and [[ascending colon|ascending]] sections. The cecum is an end point for the colon with a dead-end portion terminating with the [[appendix (anatomy)|appendix]].<ref>{{cite web |last1=Taylor |first1=Tim |title=Anatomy and Physiology Instructor |url=https://www.innerbody.com/image/dige08.html |website=InnerBody.com |publisher=Howtomedia, Inc. |access-date=28 November 2014}}</ref> | ||
The connection between the end of the small intestine (ileum) and the start (as viewed from the perspective of food being processed) of the colon (cecum) is now clearly understood, and is called the ileocecal orifice. The connection between the end of the cecum and the beginning of the ascending colon is called the cecocolic orifice. | The connection between the end of the small intestine (ileum) and the start (as viewed from the perspective of food being processed) of the colon (cecum) is now clearly understood, and is called the ileocecal orifice. The connection between the end of the cecum and the beginning of the ascending colon is called the cecocolic orifice. | ||
==Clinical significance== | ==Clinical significance== | ||
A cecal carcinoid tumor is a [[carcinoid tumor]] of the cecum. An [[appendiceal carcinoid tumor]] (a carcinoid tumor of the appendix) is sometimes found next to a cecal carcinoid.<ref>{{Cite journal |last1=Salirrosas Roncal |first1=Oscar A |last2=Tantalean Gutierrez |first2=Christian |last3=Llerena Vasquez |first3=Cesar |title=Carcinoid Tumor of the Cecal Appendix |journal=Cureus |date=2022 |volume=14 |issue=10 | | A cecal carcinoid tumor is a [[carcinoid tumor]] of the cecum. An [[appendiceal carcinoid tumor]] (a carcinoid tumor of the appendix) is sometimes found next to a cecal carcinoid.<ref>{{Cite journal |last1=Salirrosas Roncal |first1=Oscar A |last2=Tantalean Gutierrez |first2=Christian |last3=Llerena Vasquez |first3=Cesar |title=Carcinoid Tumor of the Cecal Appendix |journal=Cureus |date=2022 |volume=14 |issue=10 |article-number=e30793 |doi=10.7759/cureus.30793 |doi-access=free |issn=2168-8184 |pmc=9701446 |pmid=36447686}}</ref> | ||
[[Neutropenic enterocolitis]] (typhlitis) is the condition of inflammation of the cecum, primarily caused by bacterial infections. | [[Neutropenic enterocolitis]] (typhlitis) is the condition of inflammation of the cecum, primarily caused by bacterial infections. | ||
Over 99% of the bacteria in the gut are [[anaerobe]]s | Over 99% of the bacteria in the gut are [[anaerobe]]s<ref name="Guarner and Malagelada 2003b">{{cite journal |author=Guarner F, Malagelada JR |title=Gut flora in health and disease |journal=Lancet |volume=361 |issue=9356 |pages=512–19 |date=February 2003 |pmid=12583961 |doi=10.1016/S0140-6736(03)12489-0 |s2cid=38767655}}</ref><ref name=Sears>{{cite journal |author=Sears CL |title=A dynamic partnership: celebrating our gut flora |journal=Anaerobe |volume=11 |issue=5 |pages=247–51 |date=October 2005 |pmid=16701579 |doi=10.1016/j.anaerobe.2005.05.001}}</ref><ref name="University of Glasgow">University of Glasgow. 2005. [https://web.archive.org/web/20040526195616/http://www.gla.ac.uk/departments/humannutrition/students/resources/meden/Infection.pdf The normal gut flora.] Available through web archive. Accessed May 22, 2008</ref><ref name="Beaugerie L and Petit JC">{{cite journal |author=Beaugerie L, Petit JC |title=Microbial-gut interactions in health and disease. Antibiotic-associated diarrhoea |journal=Best Pract Res Clin Gastroenterol |volume=18 |issue=2 |pages=337–52 |date=April 2004 |pmid=15123074 |doi=10.1016/j.bpg.2003.10.002}}</ref><ref name=Vedantam>{{cite journal |author=Vedantam G, Hecht DW |title=Antibiotics and anaerobes of gut origin |journal=Curr. Opin. Microbiol. |volume=6 |issue=5 |pages=457–61 |date=October 2003 |pmid=14572537 |doi=10.1016/j.mib.2003.09.006}}</ref> but, in the cecum, [[aerobic bacteria]] reach high densities.<ref name="Prescotts">{{cite book |last2=Willey |first2=Joanne |last1=Sherwood |first1=Linda |last3=Woolverton |first3=Christopher |title=Prescott's Microbiology |url={{google books |plainurl=y |id=sBCSRAAACAAJ}} |year=2013 |isbn=978-0-07-340240-6 |publisher=McGraw Hill |location=New York |edition=9th |pages=713–21 |oclc=886600661}}</ref> | ||
==Other animals== | ==Other animals== | ||
[[File:Gastric caeca of dissected cockroach.tiff|thumb|Gastric cecum of dissected [[cockroach]]. | [[File:Gastric caeca of dissected cockroach.tiff|thumb|Gastric cecum of dissected [[cockroach]]. Scale bar, 2 mm.]] | ||
A cecum is present in most [[amniote]] species, and also in [[lungfish]], but not in any living species of [[amphibian]]. In [[reptile]]s, it is usually a single median structure, arising from the dorsal side of the large intestine. [[ | A cecum is present in most [[amniote]] species, and also in [[lungfish]], but not in any living species of [[amphibian]]. In [[reptile]]s, it is usually a single median structure, arising from the dorsal side of the large intestine. The ceca in [[bird]]s are often paired, with many exceptions; parrots, for example, do not have ceca, while others may have a single cecum or even two pairs, like the [[secretarybird]].<ref name=MP>{{cite journal |last1=Clench |first1=Mary H. |last2=Mathias |first2=John R. |title=The Avian Cecum: A Review |journal=The Wilson Bulletin |date=1995 |volume=107 |issue=1 |pages=93–121 |id={{Gale|A16787963}} {{INIST|3480481}} |jstor=4163516}}</ref> | ||
Most mammalian [[herbivore]]s have a relatively large cecum. | Most mammalian [[herbivore]]s have a relatively large cecum. In many species, it is considerably wider than the colon. For some herbivores such as [[lagomorpha|lagomorphs]] (rabbits, hares, pikas), easily digestible food is processed in the gastrointestinal tract and expelled as regular feces. But in order to get nutrients out of hard-to-digest fiber, lagomorphs ferment fiber in the cecum and then expel the contents as [[cecotrope]]s, which are reingested (cecotrophy). The cecotropes are then absorbed in the small intestine to utilize the nutrients. | ||
In contrast, obligate [[carnivore]]s, whose diets contain little or no plant matter, have a reduced cecum, which is often partially or wholly replaced by the [[appendix (anatomy)|appendix]].<ref name=VB/> Mammalian species which do not develop a cecum include [[raccoon]]s,<ref>{{cite journal |last1=Clemens |first1=Edgar T. |last2=Stevens |first2=Charles E. |title=Sites of Organic Acid Production and Patterns of Digesta Movement in the Gastro-Intestinal Tract of the Raccoon |journal=The Journal of Nutrition |date=1 June 1979 |volume=109 |issue=6 |pages=1110–1116 |doi=10.1093/jn/109.6.1110 |pmid=448450 |url=https://www.sciencedirect.com/science/article/abs/pii/S0022316623277147 |access-date=1 June 2024 |issn=0022-3166|url-access=subscription }}</ref> [[bear]]s,<ref>{{cite journal |last1=Jones |first1=James D. |last2=Zollman |first2=Paul E. |title=Black Bear (Ursus americanus) Bile Composition: Seasonal Changes |journal=Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology |date=17 March 1997 |volume=118 |issue=3 |pages=387–390 |doi=10.1016/S0742-8413(97)00176-X |pmid=9467890 |url=https://www.sciencedirect.com/science/article/abs/pii/S074284139700176X |access-date=1 June 2024|url-access=subscription }}</ref> and the [[red panda]].<ref>{{cite journal |last1=Wei |first1=F. |last2=Feng |first2=Z. |last3=Wang |first3=Z. |last4=Zhou |first4=A. |last5=Hu |first5=J. |title=Nutrient and energy requirements of red panda (Ailurus fulgens) during lactation |journal=Mamm |date=1 January 1999 |volume=63 |issue=1 |pages=3–10 |doi=10.1515/mamm.1999.63.1.3 |url=https://www. | In contrast, obligate [[carnivore]]s, whose diets contain little or no plant matter, have a reduced cecum, which is often partially or wholly replaced by the [[appendix (anatomy)|appendix]].<ref name=VB/> Mammalian species which do not develop a cecum include [[raccoon]]s,<ref>{{cite journal |last1=Clemens |first1=Edgar T. |last2=Stevens |first2=Charles E. |title=Sites of Organic Acid Production and Patterns of Digesta Movement in the Gastro-Intestinal Tract of the Raccoon |journal=The Journal of Nutrition |date=1 June 1979 |volume=109 |issue=6 |pages=1110–1116 |doi=10.1093/jn/109.6.1110 |pmid=448450 |url=https://www.sciencedirect.com/science/article/abs/pii/S0022316623277147 |access-date=1 June 2024 |issn=0022-3166 |url-access=subscription}}</ref> [[bear]]s,<ref>{{cite journal |last1=Jones |first1=James D. |last2=Zollman |first2=Paul E. |title=Black Bear (Ursus americanus) Bile Composition: Seasonal Changes |journal=Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology |date=17 March 1997 |volume=118 |issue=3 |pages=387–390 |doi=10.1016/S0742-8413(97)00176-X |pmid=9467890 |url=https://www.sciencedirect.com/science/article/abs/pii/S074284139700176X |access-date=1 June 2024 |url-access=subscription}}</ref> and the [[red panda]].<ref>{{cite journal |last1=Wei |first1=F. |last2=Feng |first2=Z. |last3=Wang |first3=Z. |last4=Zhou |first4=A. |last5=Hu |first5=J. |title=Nutrient and energy requirements of red panda (Ailurus fulgens) during lactation |journal=Mamm |date=1 January 1999 |volume=63 |issue=1 |pages=3–10 |doi=10.1515/mamm.1999.63.1.3 |url=https://www.degruyterbrill.com/document/doi/10.1515/mamm.1999.63.1.3/html |access-date=1 June 2024 |language=en |issn=1864-1547 |url-access=subscription}}</ref> [[Hyrax]]es, unlike other mammals, have two paired ceca.<ref name=VB>{{cite book |last1=Romer |first1=Alfred Sherwood |last2=Parsons |first2=Thomas S. |year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location=Philadelphia |pages=353–54 |isbn=978-0-03-910284-5}}</ref> | ||
Many fish have a number of small outpockets, called ''pyloric ceca'', along their intestine; despite the name, they are not [[homology (biology)|homologous]] with the cecum of amniotes – their | Many fish have a number of small outpockets, called ''pyloric ceca'', along their intestine; despite the name, they are not [[homology (biology)|homologous]] with the cecum of amniotes – their function is to increase the overall area of the digestive epithelium.<ref name=VB/> Some invertebrates, such as squid,<ref name=Williams1910>{{cite book |last1=Williams |first1=Leonard Worcester |title=The anatomy of the common squid: ''Loligo pealii'', Lesueur |date=1910 |doi=10.5962/bhl.title.27291 |oclc=697639284 |url=https://www.biodiversitylibrary.org/item/69772}}</ref> may also have structures with the same name, but these have no relationship with those of vertebrates. | ||
==Gallery== | ==Gallery== | ||
<gallery> | <gallery> | ||
File:Blausen 0604 LargeIntestine2.png|Illustration of the large intestine | File:Blausen 0604 LargeIntestine2.png|Illustration of the large intestine | ||
File:Monogastric Digestive System.webp|Illustration of human and rabbit cecum | |||
File:Cecum and ileum.JPG|Cecum and ileum | File:Cecum and ileum.JPG|Cecum and ileum | ||
File:Ileo-cecal valve.JPG|Ileo-cecal valve | File:Ileo-cecal valve.JPG|Ileo-cecal valve | ||
| Line 67: | Line 71: | ||
File:Gray536.png|Arteries of cecum and [[Appendix (anatomy)|vermiform process]] | File:Gray536.png|Arteries of cecum and [[Appendix (anatomy)|vermiform process]] | ||
File:Gray1044.png|Inferior ileocecal fossa | File:Gray1044.png|Inferior ileocecal fossa | ||
File:Ileocecal valve.jpg|[[Colonoscopy|Endoscopic]] image of cecum with arrow pointing to [[ileocecal valve]] in foreground | File:Ileocecal valve.jpg|[[Colonoscopy|Endoscopic]] image of cecum with arrow pointing to [[ileocecal valve]] in foreground | ||
</gallery> | </gallery> | ||
| Line 79: | Line 83: | ||
{{Commons category|Cecum}} | {{Commons category|Cecum}} | ||
{{Wiktionary|cecum}} | {{Wiktionary|cecum}} | ||
* {{SUNYAnatomyFigs|37|03|08}}—"Abdominal organs in situ | * {{SUNYAnatomyFigs|37|03|08}}—"Abdominal organs in situ" | ||
* {{SUNYAnatomyFigs|37|06|09}}—"The larger intestine | * {{SUNYAnatomyFigs|37|06|09}}—"The larger intestine" | ||
* {{SUNYAnatomyFigs|39|05|09}}—"The cecum with the distal portion of the ileum | * {{SUNYAnatomyFigs|39|05|09}}—"The cecum with the distal portion of the ileum" | ||
* {{SUNYAnatomyLabs|39|14|01|01}}—"Incisions of the Cecum" | * {{SUNYAnatomyLabs|39|14|01|01}}—"Incisions of the Cecum" | ||
* {{ViennaCrossSection|pelvis/pelvis-e12-2}} | * {{ViennaCrossSection|pelvis/pelvis-e12-2}} | ||
* [https://web.archive.org/web/20060715020910/http://learning.mgccc.cc.ms.us/science/cat/sld021.htm Photo at mgccc.cc.ms.us] | * [https://web.archive.org/web/20060715020910/http://learning.mgccc.cc.ms.us/science/cat/sld021.htm Photo at mgccc.cc.ms.us] | ||
* | * {{Webarchive |title=Video clip of worms in the Cecum - N Engl J Med 2006;354(13):e12 |url=https://web.archive.org/web/20100129103841/http://content.nejm.org/cgi/content/full/354/13/e12/DC1 |date=2010-01-29}} (Supplement to {{doi|10.1056/NEJMicm040931}}) | ||
{{ | {{Gastrointestinal tract}} | ||
{{Authority control}} | {{Authority control}} | ||
[[Category:Digestive system]] | [[Category:Digestive system]] | ||
[[Category:Latin words and phrases]] | [[Category:Latin words and phrases]] | ||
Latest revision as of 00:13, 22 October 2025
Template:Short description Script error: No such module "redirect hatnote". Script error: No such module "Distinguish". Script error: No such module "Infobox".Template:Template otherTemplate:Main other
The cecum (UK:Script error: No such module "Check for unknown parameters". caecum, pronouncedScript error: No such module "Check for unknown parameters". Template:IPAc-en; plural ceca or UK:Script error: No such module "Check for unknown parameters". caeca, pronouncedScript error: No such module "Check for unknown parameters". Template:IPAc-en) is a pouch within the peritoneum that is considered to be the beginning of the large intestine.[1] It is typically located on the right side of the body (the same side of the body as the appendix, to which it is joined). The term stems from the Latin caecus, meaning "blind".
It receives chyme from the ileum, and connects to the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve (ICV), also called Bauhin's valve. It is also separated from the colon by the cecocolic junction. While the cecum is usually intraperitoneal, the ascending colon is retroperitoneal.[2]
In herbivores, the cecum stores food material where bacteria are able to break down the cellulose. In humans, the cecum is involved in absorption of salts and electrolytes and lubricates the solid waste that passes into the large intestine.[3]
Structure
Development
The cecum and appendix are derived from the bud of cecum that forms during week six in the midgut next to the apex of the umbilical herniation.[5] Specifically, the cecum and appendix are formed by the enlargement of the postarterial segment of the midgut loop. The proximal part of the bud grows rapidly to form the cecum. The lateral wall of the cecum grows much more rapidly than the medial wall, with the result that the point of attachment of the appendix comes to lie on the medial side.Script error: No such module "Unsubst". The cecum's position changes after the midgut rotates and the ascending colon elongates, and the accumulation of meconium inside the cecum may result in the latter's increased diameter.[5]
History
Etymology
The term cecum comes from Latin (intestinum) caecum, literally 'blind intestine', in the sense 'blind gut' or 'cul de sac'.[6] It is a direct translation from Ancient Greek Script error: No such module "Lang". (Script error: No such module "Lang".) Template:Transliteration (Template:Transliteration). Thus the inflammation of the cecum is called typhlitis.
In dissections by the Greek philosophers, the connection between the ileum of the small intestine and the cecum was not fully understood. Most of the studies of the digestive tract were done on animals and the results were compared to human structures.[7]
The junction between the small intestine and the colon, called the ileocecal valve, is so small in some animals that it was not considered to be a connection between the small and large intestines. During a dissection, the colon could be traced from the rectum, to the sigmoid colon, through the descending, transverse, and ascending sections. The cecum is an end point for the colon with a dead-end portion terminating with the appendix.[8]
The connection between the end of the small intestine (ileum) and the start (as viewed from the perspective of food being processed) of the colon (cecum) is now clearly understood, and is called the ileocecal orifice. The connection between the end of the cecum and the beginning of the ascending colon is called the cecocolic orifice.
Clinical significance
A cecal carcinoid tumor is a carcinoid tumor of the cecum. An appendiceal carcinoid tumor (a carcinoid tumor of the appendix) is sometimes found next to a cecal carcinoid.[9]
Neutropenic enterocolitis (typhlitis) is the condition of inflammation of the cecum, primarily caused by bacterial infections.
Over 99% of the bacteria in the gut are anaerobes[10][11][12][13][14] but, in the cecum, aerobic bacteria reach high densities.[15]
Other animals
A cecum is present in most amniote species, and also in lungfish, but not in any living species of amphibian. In reptiles, it is usually a single median structure, arising from the dorsal side of the large intestine. The ceca in birds are often paired, with many exceptions; parrots, for example, do not have ceca, while others may have a single cecum or even two pairs, like the secretarybird.[16]
Most mammalian herbivores have a relatively large cecum. In many species, it is considerably wider than the colon. For some herbivores such as lagomorphs (rabbits, hares, pikas), easily digestible food is processed in the gastrointestinal tract and expelled as regular feces. But in order to get nutrients out of hard-to-digest fiber, lagomorphs ferment fiber in the cecum and then expel the contents as cecotropes, which are reingested (cecotrophy). The cecotropes are then absorbed in the small intestine to utilize the nutrients.
In contrast, obligate carnivores, whose diets contain little or no plant matter, have a reduced cecum, which is often partially or wholly replaced by the appendix.[17] Mammalian species which do not develop a cecum include raccoons,[18] bears,[19] and the red panda.[20] Hyraxes, unlike other mammals, have two paired ceca.[17]
Many fish have a number of small outpockets, called pyloric ceca, along their intestine; despite the name, they are not homologous with the cecum of amniotes – their function is to increase the overall area of the digestive epithelium.[17] Some invertebrates, such as squid,[21] may also have structures with the same name, but these have no relationship with those of vertebrates.
Gallery
-
Illustration of the large intestine
-
Illustration of human and rabbit cecum
-
Cecum and ileum
-
Ileo-cecal valve
-
Cecum
-
Arteries of cecum and vermiform process
-
Inferior ileocecal fossa
-
Endoscopic image of cecum with arrow pointing to ileocecal valve in foreground
See also
References
External links
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- Anatomy figure: 37:03-08 at Human Anatomy Online, SUNY Downstate Medical Center—"Abdominal organs in situ"
- Anatomy figure: 37:06-09 at Human Anatomy Online, SUNY Downstate Medical Center—"The larger intestine"
- Anatomy figure: 39:05-09 at Human Anatomy Online, SUNY Downstate Medical Center—"The cecum with the distal portion of the ileum"
- Anatomy photo:39:14-0101 at the SUNY Downstate Medical Center—"Incisions of the Cecum"
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- Photo at mgccc.cc.ms.us
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- ↑ University of Glasgow. 2005. The normal gut flora. Available through web archive. Accessed May 22, 2008
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