Cecum

Cecum
Cecum
Stomach colon rectum diagram.svg
Gray1043.png
Superior ileocecal fossa (cecum labeled at bottom left)
Gray's subject #249 1177
Precursor Midgut
MeSH Cecum
Dorlands/Elsevier Cecum

The cecum or caecum (play /ˈskəm/, plural /ˈskə/; from the Latin caecus meaning blind) is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve (ICV) or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic junction. The appendix is connected to the cecum[citation needed]. The cecum is usually peritoneal, while the ascending colon is retroperitoneal [1].


Contents

Variation Across Species

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. Birds typically have two paired ceca, as, unlike other mammals, do hyraxes.[2]

Most mammalian herbivores have a relatively large cecum, hosting a large number of bacteria, which aid in the enzymatic breakdown of plant materials such as cellulose; in many species, it is considerably wider than the colon. In contrast, obligatory carnivores, whose diets contain little or no plant material, have a reduced cecum, which is often partially or wholly replaced by the vermiform appendix.[2] Over 99% of the bacteria in the gut flora are anaerobes,[3][4][5][6][7] but in the cecum, aerobic bacteria reach high densities.[3]

Many fish have a number of small outpocketings, called pyloric ceca, along their intestine; despite the name they are not homologous with the cecum of amniotes, and their purpose is to increase the overall area of the digestive epithelium.[2] Some invertebrates, such as squid,[8] may also have structures with the same name, but these have no relationship with those of vertebrates.

Etymology

The term cecum comes from the Latin caecum, literally "blind", here in the sense "blind gut" or "cul de sac".[citation needed]

In dissections by the Greek philosophers, the connection between the ileum of the small intestines 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.[citation needed]


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 colon seemed to dead-end into the cecum, or cul-de-sac.[citation needed]


The connection between the end of the small intestine (ileum) and the start of the colon (cecum) is now clearly understood, but the name has not changed.[citation needed]

Development

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.[citation needed]

Diseases

A cecal carcinoid tumor is a carcinoid tumor of the cecum. A appendiceal carcinoid tumor (a carcinoid tumor of the appendix) is sometimes found next to a cecal carcinoid.[citation needed]


See also

Additional images

References

  1. ^ http://download.videohelp.com/vitualis/med/large_intestine.htm
  2. ^ a b c Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 353–354. ISBN 0-03-910284-X. 
  3. ^ a b Guarner F, Malagelada JR (February 2003). "Gut flora in health and disease". Lancet 361 (9356): 512–9. doi:10.1016/S0140-6736(03)12489-0. PMID 12583961. 
  4. ^ Sears CL (October 2005). "A dynamic partnership: celebrating our gut flora". Anaerobe 11 (5): 247–51. doi:10.1016/j.anaerobe.2005.05.001. PMID 16701579. 
  5. ^ University of Glasgow. 2005. The normal gut flora. Available through web archive. Accessed May 22, 2008
  6. ^ Beaugerie L, Petit JC (April 2004). "Microbial-gut interactions in health and disease. Antibiotic-associated diarrhoea". Best Pract Res Clin Gastroenterol 18 (2): 337–52. doi:10.1016/j.bpg.2003.10.002. PMID 15123074. http://linkinghub.elsevier.com/retrieve/pii/S1521691803001276. 
  7. ^ Vedantam G, Hecht DW (October 2003). "Antibiotics and anaerobes of gut origin". Curr. Opin. Microbiol. 6 (5): 457–61. doi:10.1016/j.mib.2003.09.006. PMID 14572537. http://linkinghub.elsevier.com/retrieve/pii/S1369527403001176. 
  8. ^ Williams, L.W. (1910). The anatomy of the common squid : Loligo pealii, Lesueur. American Museum Of Natural History. 

External links


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • cecum — CÉCUM s.n. v. cec2. Trimis de valeriu, 13.09.2007. Sursa: DEX 98  cécum s. n., pl. cécumuri Trimis de siveco, 07.11.2006. Sursa: Dicţionar ortografic  CÉCUM s.n. v. cec2 …   Dicționar Român

  • cecum — n. The {caecum}, the cavity in which the large intestine begins and into which the ileum opens. Syn: caecum, blind gut. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • cecum — variant of CAECUM (Cf. caecum) …   Etymology dictionary

  • cecum — (Brit. caecum) ► NOUN (pl. ceca) ▪ a pouch connected to the junction of the small and large intestines. DERIVATIVES cecal adjective. ORIGIN from Latin intestinum caecum blind gut …   English terms dictionary

  • cecum — [sē′kəm] n. pl. ceca [sē′kə] [ModL < L caecum < intestinum caecum, blind intestine < caecus, blind < IE base * kai ka, one eyed, squinting > OIr caech, one eyed, blind, Goth haihs, one eyed] 1. the pouch that is the beginning of… …   English World dictionary

  • cecum — (Order Cladocera): Digestive cecum [Stachowitsch, 1992]. (Order Notostraca): One of two outpocketings of midgut. Elongate and extensively branched with carapace. Opens into digestive tract posterior to esophagus/midgut border. (Syn. midgut… …   Crustacea glossary

  • Cecum — The cecum (also spelled caecum), the first portion of the large bowel, situated in the lower right quadrant of the abdomen. The cecum receives fecal material from the small bowel (ileum) which opens into it. The appendix is attached to the cecum …   Medical dictionary

  • cecum — cecal, adj. cecally, adv. /see keuhm/, n., pl. ceca / keuh/. Anat., Zool. a cul de sac, esp. that in which the large intestine begins. Also, caecum. [1715 25; short for L intestinum caecum blind gut] * * * ▪ …   Universalium

  • cecum — caecum cae cum, n.; pl. {C[ae]cums}, L. {C[ae]ca}. [L. caecus blind, invisible, concealed.] (Anat.) (a) A cavity open at one end, as the blind end of a canal or duct. (b) The blind part of the large intestine beyond the entrance of the small… …   The Collaborative International Dictionary of English

  • Cecum — Das Caecum in Detailansicht, mit dem terminalen Ileum und Ileozäkalklappe, die Sonde zeigt den Eingang in die Appendix. Der Blinddarm (lat. Caecum, Coecu …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”