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503:. In deuterostomes, the original dent becomes the anus while the gut eventually tunnels through to make another opening, which forms the mouth. The protostomes were so named because it was thought that in their embryos the dent formed the mouth first (
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meaning "first") and the anus was formed later at the opening made by the other end of the gut. Research from 2001 shows the edges of the dent close up in the middles of protosomes, leaving openings at the ends which become the mouths and anuses.
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The development of the anus was an important stage in the evolution of multicellular animals. It appears to have happened at least twice, following different paths in
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Arendt, D.; Technau, U. & Wittbrodt, J. (4 January 2001). "Evolution of the bilaterian larval foregut".
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This article is about the anuses of animals in general. For details specific to humans, see
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mammals also have a cloaca, which is thought to be a feature inherited from the earliest
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37:"Pooper" redirects here. For the fan nickname of the fictional Pokémon species, see
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Langstroth, Lovell; Libby
Langstroth; Todd Newberry; Monterey Bay Aquarium (2000).
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438:. This accompanied or facilitated other important evolutionary developments: the
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Helms, Doris R.; Helms, Carl W.; Kosinski, Robert J.; Cummings, John C. (1997).
427:, although the channels flowing to that orifice are almost completely separate.
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grows an anus, which then disappear when it is no longer needed.
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358:. Passage of feces through the anus is typically controlled by
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Bowel contents that pass through the anus include the gaseous
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What is a warty comb jelly? | BBC Science Focus
Magazine
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558: – Medical functional test of the anus and rectum
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Chin, K.; Erickson, G.M.; et al. (1998-06-18).
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365:, and failure to stop unwanted passages results in
30:"Butthole" redirects here. For the slang word, see
612:A living bay: the underwater world of Monterey Bay
585:Biology in the Laboratory With BioBytes 3.1 CD-ROM
552: – Functional segment of the large intestine
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415:mammals have completely separate orifices for
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86:Formation of anus in proto- and deuterostomes
425:another for both urination and reproduction
615:. University of California Press. p.
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698:(25). Society for Science &: 391.
564: – Birth defect of malformed rectum
499:, the first phase in the growth of the
27:Digestive tract waste expulsion opening
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251:, 'ring' or 'circle') is the external
483:In animals at least as complex as an
684:"Getting the scoop from the poop of
383:use a similar orifice (known as the
271:. Its function is to facilitate the
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267:), i.e. the opposite end from the
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642:"A king-sized theropod coprolite"
320:have been extracted, for example
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588:. W. H. Freeman. p. 36-12.
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163:Superficial inguinal lymph nodes
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682:Monastersky, R. (1998-06-20).
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495:, which deepens to become the
491:forms a dent on one side, the
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316:material after the digestible
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540:The dictionary definition of
275:of wastes that remain after
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528:Evolutionary biology portal
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211:Anatomical terminology
151:Inferior rectal nerves
127:Inferior rectal artery
48:. For other uses, see
50:Anus (disambiguation)
812:at Wikimedia Commons
440:bilaterian body plan
139:Inferior rectal vein
763:2001Natur.409...81A
660:1998Natur.393..680C
556:Anorectal manometry
286:and the semi-solid
367:fecal incontinence
808:Media related to
626:978-0-520-22149-9
595:978-0-7167-3146-7
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16:(Redirected from
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831:Digestive system
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714:. Archived from
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562:Imperforate anus
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339:-containing
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192:A05.7.05.013
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680:Summary at
497:archenteron
469:Development
432:protostomes
343:; and dead
333:metabolites
312:; residual
259:end of the
169:Identifiers
820:Categories
722:2009-04-24
569:References
550:Anal canal
493:blastopore
475:Protostome
452:arthropods
448:metamerism
417:defecation
405:Marsupials
393:egg-laying
389:copulation
373:Amphibians
363:sphincters
354:and other
350:or excess
115:Alimentary
103:Proctodeum
71:Anus of a
46:Human anus
485:earthworm
421:urination
413:placental
397:Monotreme
348:epithelia
337:bilirubin
322:cellulose
318:nutrients
277:digestion
273:expulsion
98:Precursor
779:11343117
514:See also
401:amniotes
377:reptiles
360:muscular
330:excreted
227:In most
18:Butthole
787:4406268
759:Bibcode
712:4010364
676:4343329
656:Bibcode
345:mucosal
299:pellets
255:at the
247:; from
229:animals
92:Details
32:Asshole
785:
777:
750:Nature
710:
686:T. rex
674:
647:Nature
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592:
506:proto–
489:embryo
487:, the
446:, and
444:coelom
442:, the
409:vagina
385:cloaca
326:lignin
284:flatus
241:anuses
231:, the
122:Artery
110:System
39:Wooper
783:S2CID
708:JSTOR
672:S2CID
381:birds
335:like
306:seeds
292:bones
288:feces
269:mouth
265:bowel
249:Latin
215:[
175:Latin
158:Lymph
146:Nerve
826:Anus
810:Anus
775:PMID
621:ISBN
590:ISBN
543:anus
477:and
434:and
391:and
379:and
341:bile
314:food
308:and
296:hair
257:exit
233:anus
204:3022
187:TA98
180:anus
134:Vein
60:Anus
767:doi
755:409
700:doi
696:153
664:doi
652:393
617:244
501:gut
457:In
324:or
245:ani
243:or
237:pl.
199:TA2
73:dog
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
