Abdomen 3191861 224602779 2008-07-09T16:42:36Z Dysmorodrepanis 303688 +dab [[Image:Abdomen-head-thorax-en.svg|thumb|right|250px|The abdomen in a human and an ant.]] {{For|the human abdomen|human abdomen}} :''"Abdominal" redirects here. For the [[rapper]] from [[Canada]], see [[Abdominal (rapper)]].'' In [[vertebrate]]s such as [[mammal]]s the abdomen (belly) constitutes the part of the body between the [[thorax]] (chest) and [[pelvis]]. The region enclosed by the abdomen is termed the [[abdominal cavity]]. In [[arthropod]]s it is the most distal section of the body which lies behind the thorax or [[cephalothorax]]<ref>Abdomen. (n.d.). Dictionary.com Unabridged (v 1.1). URL: http://dictionary.reference.com/browse/abdomen [Accessed: 22 Oct 2007]</ref><ref>Abdomen. Dictionary.com. The American Heritage Dictionary of the English Language, 4th Edition. URL: http://dictionary.reference.com/browse/abdomen [Accessed: 22 October 2007].</ref>. ==Vertebrates== In vertebrates the abdomen is a large cavity enclosed by the abdominal muscles [[ventral]]y and [[lateral]]y and by [[vertebral column]] dorsally. Lower ribs can also enclose ventral and lateral walls. Abdominal cavity is continuous with pelvic cavity. It is separated from [[thoracic cavity]] by [[diaphragm]]. Structures such as the [[aorta]], inferior [[vena cava]] and [[esophagus]] pass through the diaphragm. Both abdominal cavity and pelvic cavity are lined by a serous membrane known as [[parietal peritoneum]]. This membrane is continuous with [[visceral peritoneum]] lining the organs<ref>Peritoneum. The Veterinary Dictionary. Elsevier, 2007. http://www.answers.com/topic/peritoneum [Accessed: 22 Oct 2007)</ref>. Abdomen in vertebrates contains a number of [[organ (anatomy)|organs]] belonging for instance to [[digestive tract]] and [[urinary system]]. ===Abdominal organs=== * '''Digestive tract''': [[Stomach]], [[small intestine]], [[large intestine]] with [[cecum]] and [[appendix (anatomy)|appendix]] * '''Accessory organs of the digestive tract''': [[Liver]], [[gallbladder]] and [[pancreas]] * '''Urinary system''': [[Kidney]]s and [[ureters]] * '''Other organs''': [[Spleen]] Abdominal organs can be highly specialized in some animals. For example the stomach of [[ruminant]]s (a [[suborder]] of mammals) is divided into four chambers - [[rumen]], [[reticulum]], [[omasum]] and [[abomasum]].<ref>"Ruminant." The Veterinary Dictionary. Elsevier, 2007. http://www.answers.com/topic/ruminant [Accessed: 22 Oct 2007].</ref> ==Invertebrates== [[Image:Scheme ant worker anatomy-en.svg|thumb|right|300px|In the worker ant, the abdomen consists of the [[propodeum]] fused to the [[thorax]] and the [[metasoma]], itself divided into the narrow [[petiole (insect)|petiole]] and bulbous [[gaster]].]] The invertebrate abdomen is built up of a series of concave upper plates known as [[tergite]]s and convex lower plates known as [[sternite]]s, the whole being held together by a tough yet stretchable membrane. The abdomen contains the insect's digestive tract and reproductive organs, it consists of eleven segments in most orders of insects though the eleventh segment is absent in the adult of most higher orders. The number of these segments does vary from species to species with the number of segments visible reduced to only seven in the common [[honeybee]]. In the [[Collembola]] (Springtails) the abdomen has only six segments. The abdomen is sometimes highly modified. In [[ant]]s, the first segment of the abdomen is fused to the [[thorax]] and called the [[propodeum]]. The second segment forms the narrow [[petiole (insect)|petiole]]. Some ants have an additional [[postpetiole]] segment, and the remaining segments form the bulbous [[gaster]].[http://www.desertants.org/indexpages/terminology.html] The petiole and gaster (abdominal segments 2 and onward) are collectively called the [[metasoma]]. Unlike other Arthropods, insects possess no legs on the abdomen in adult form, though the [[Protura]] do have rudimentary leg-like appendages on the first three abdominal segments, and [[Archaeognatha]] possess small, articulated "styli" which are sometimes considered to be rudimentary appendages. Many larval insects including the [[Lepidoptera]] and the [[Symphyta]] (Sawflies) have fleshy appendages called [[proleg]]s on their abdominal segments (as well as their more familiar thoracic legs), which allow them to grip onto the edges of plant leaves as they walk around. ==See also== *[[Human abdomen]] *[[Opisthosoma]] *[[Metasoma]] *[[Abdominal trauma]] ==References== <references/> [[Category:Abdomen]] [[Category:Animal anatomy]] [[ar:بطن]] [[ast:Abdome]] [[bg:Корем]] [[cs:Břicho]] [[da:Bughule]] [[de:Abdomen]] [[es:Abdomen]] [[eo:Ventro]] [[eu:Abdomen]] [[fr:Abdomen]] [[gl:Abdome]] [[io:Abdomino]] [[id:Abdomen]] [[ia:Abdomine]] [[is:Afturbolur]] [[it:Addome]] [[he:בטן]] [[lt:Pilvelis]] [[ln:Libumu]] [[mk:Стомачна празнина]] [[nl:Buik]] [[nds-nl:Boek (lichem)]] [[ja:腹]] [[no:Bakkropp]] [[nn:Abdomen]] [[pl:Odwłok]] [[pt:Abdómen]] [[qu:Wiksa]] [[ru:Брюшко]] [[simple:Abdomen]] [[sv:Buken]] [[tl:Puson]] [[te:ఉదరము]] [[tr:Karın (anatomi)]] [[uk:Черевце]] [[yi:בויך]] [[zh:腹]]