The Birsig is a rather small river in eastern France and northern Switzerland . Its source is in the village Biederthal , in the French Haut-Rhin department, near the Swiss border. The Birsig is about 21 kilometres (13 mi) long, and its watershed area is about 82 square kilometres (32 sq mi). It flows variably through Swiss and French territory and through the Birsig Valley . Afterwards it passes the city of Basel , where it enters the Rhine (left bank).
18-424: The river Birsig originally flowed openly through Basel, but the river was long ago channelled and its banks built up to prevent water damage to the houses. The river flowed directly along the houses in the lower part of the city, where many bridges were built over. It took the fecal waste from the houses and was therefore called "the city's big cloaca ", which favoured the outbreak of cholera and typhus . Nowadays
36-418: A cloaca, which is thought to be a feature inherited from the earliest amniotes . Marsupials have a single orifice for excreting both solids and liquids and, in females, a separate vagina for reproduction. Female placental mammals have completely separate orifices for defecation , urination , and reproduction; males have one opening for defecation and another for both urination and reproduction , although
54-411: A cloacal kiss in most birds. Birds that mate using this method touch their cloacae together, in some species for only a few seconds, sufficient time for sperm to be transferred from the male to the female. For palaeognaths and waterfowl , the males do not use the cloaca for reproduction, but have a phallus . One study has looked into birds that use their cloaca for cooling. Among falconers ,
72-461: A few exceptions noted below, mammals have no cloaca. Even in the marsupials that have one, the cloaca is partially subdivided into separate regions for the anus and urethra . The monotremes (egg-laying mammals) possess a true cloaca. In marsupials , the genital tract is separate from the anus, but a trace of the original cloaca does remain externally. This is one of the features of marsupials (and monotremes) that suggest their basal nature, as
90-577: Is the rear orifice that serves as the only opening for the digestive , reproductive , and urinary tracts (if present) of many vertebrate animals. All amphibians , reptiles , birds , and a few mammals ( monotremes , afrosoricids , and marsupial moles ) have this orifice, from which they excrete both urine and feces ; this is in contrast to most placental mammals, which have two or three separate orifices for evacuation and reproduction. Excretory openings with analogous purpose in some invertebrates are also sometimes called cloacae. Mating through
108-499: Is where reproductive activity occurs. Some turtles , especially those specialized in diving, are highly reliant on cloacal respiration during dives. They accomplish this by having a pair of accessory air bladders connected to the cloaca, which can absorb oxygen from the water. Sea cucumbers use cloacal respiration. The constant flow of water through it has allowed various fish , polychaete worms and even crabs to specialize to take advantage of it while living protected inside
126-455: The amniotes from which mammals evolved had a cloaca, and probably so did the earliest mammals . Unlike other marsupials, marsupial moles have a true cloaca. This fact has been used to argue that they are not marsupials. Most adult placental mammals have no cloaca. In the embryo, the embryonic cloaca divides into a posterior region that becomes part of the anus, and an anterior region that develops depending on sex: in males, it forms
144-422: The development of the urinary and reproductive organs . However, a few human congenital disorders result in persons being born with a cloaca, including persistent cloaca and sirenomelia (mermaid syndrome). In reptiles, the cloaca consists of the urodeum , proctodeum , and coprodeum . Some species have modified cloacae for increased gas exchange (see reptile respiration and reptile reproduction ). This
162-425: The embryo forms a dent on one side, the blastopore , which deepens to become the archenteron , the first phase in the growth of the gut . 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 ( proto– meaning "first") and
180-481: The expulsion of wastes that remain after digestion . Bowel contents that pass through the anus include the gaseous flatus and the semi-solid feces , which (depending on the type of animal) include: indigestible matter such as bones , hair pellets , endozoochorous seeds and digestive rocks ; residual food material after the digestible nutrients have been extracted, for example cellulose or lignin ; ingested matter which would be toxic if it remained in
198-402: The penile urethra , while in females, it develops into the vestibule or urogenital sinus that receives the urethra and vagina. However, some placental mammals retain a cloaca as adults: those are members of the order Afrosoricida (small mammals native to Africa) as well as some shrews . Being placental animals, humans have an embryonic cloaca which divides into separate tracts during
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#1732783489838216-819: The Birsig is covered over for most of its course in Basel; there are just a few hundred meters around the city zoo where the Birsig can be seen openly. This article related to a river in Switzerland is a stub . You can help Misplaced Pages by expanding it . This article related to a river in France is a stub . You can help Misplaced Pages by expanding it . Cloaca A cloaca ( / k l oʊ ˈ eɪ k ə / kloh- AY -kə ), pl. : cloacae ( / k l oʊ ˈ eɪ s i / kloh- AY -see or / k l oʊ ˈ eɪ k i / kloh- AY -kee ), or vent ,
234-399: The body was built of repeated "modules" which could later specialize, such as the heads of most arthropods , which are composed of fused, specialized segments. In comb jellies , there are species with one and sometimes two permanent anuses, species like the warty comb jelly grows an anus, which then disappear when it is no longer needed. In animals at least as complex as an earthworm ,
252-416: The channels flowing to that orifice are almost completely separate. 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 protostomes and deuterostomes . This accompanied or facilitated other important evolutionary developments: the bilaterian body plan , the coelom , and metamerism , in which
270-482: The cloaca is called cloacal copulation and cloacal kissing. The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes . The word is from the Latin verb cluo , "(I) cleanse", thus the noun cloaca , " sewer , drain". Birds reproduce using their cloaca; this occurs during
288-406: The cucumber. At night, many of these species emerge through the anus of the sea cucumber in search of food. Anus In mammals , invertebrates and most fish , the anus ( pl. : anuses or ani ; from Latin , 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract ( bowel ), i.e. the opposite end from the mouth . Its function is to facilitate
306-510: The digestive tract; excreted metabolites like bilirubin -containing bile ; and dead mucosal epithelia or excess gut bacteria and other endosymbionts . Passage of feces through the anus is typically controlled by muscular sphincters , and failure to stop unwanted passages results in fecal incontinence . Amphibians , reptiles and birds use a similar orifice (known as the cloaca ) for excreting liquid and solid wastes, for copulation and egg-laying . Monotreme mammals also have
324-431: The word vent is also a verb meaning "to defecate". Among fish, a true cloaca is present only in elasmobranchs (sharks and rays) and lobe-finned fishes . In lampreys and in some ray-finned fishes , part of the cloaca remains in the adult to receive the urinary and reproductive ducts, although the anus always opens separately. In chimaeras and most teleosts , however, all three openings are entirely separated. With
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