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35-424: 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

70-423: A catheter can be inserted through the urethra to drain urine from the bladder, called an indwelling urinary catheter ; or, to bypass the urethra, a catheter may be directly inserted through the abdominal wall into the bladder, called a suprapubic catheter . This may be to relieve or bypass an obstruction, to monitor how much urine someone produces , or because a person has difficulty urinating, for example due to

105-425: A neurological cause such as multiple sclerosis . Complications that are associated with catheter insertion can include catheter-associated infections , injury to the urethra or nearby structures, or pain. In all mammals , with the exception of monotremes , and in both sexes, the urethra serves primarily to drain and excrete urine, which in mammals, collects in the urinary bladder and is released from there into

140-411: 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 ,

175-461: 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

210-400: A pressurized stream. Following this, the urethra re-establishes muscle tone by contracting the smooth muscle layer, and the bladder returns to a relaxed, quiescent state. Urethral smooth muscle cells are mechanically coupled to each other to coordinate mechanical force and electrical signaling in an organized, unitary fashion. The male urethra is the conduit for semen during orgasm . Urine

245-421: A result of insertion of foreign bodies into the urethra such as an electrical wire. Hypospadias and epispadias are forms of abnormal development of the urethra in the male, where the meatus is not located at the distal end of the penis (it occurs lower than normal with hypospadias, and higher with epispadias). In a severe chordee , the urethra can develop between the penis and the scrotum. A tube called

280-404: A sample of urine for an inspection for malignant cells under a microscope, called cytology , as well as examination with a flexible camera through the urethra, called urethroscopy . If a malignancy is found, a biopsy will be taken, and a CT scan will be performed of other body parts (a CT scan of the chest, abdomen and pelvis ) to look for additional metastatic lesions. After the cancer

315-456: Is blood in the urine ; a physical medical examination may be otherwise normal, except in late disease. Cancer of the urethra is most often due to cancer of the cells lining the urethra, called transitional cell carcinoma , although it can more rarely occur as a squamous cell carcinoma if the type of cells lining the urethra have changed, such as due to a chronic schistosomiasis infection. Investigations performed usually include collecting

350-399: Is staged , treatment may involve chemotherapy . Passage of kidney stones through the urethra can be painful. Damage to the urethra, such as by kidney stones, chronic infection, cancer, or from catheterisation, can lead to narrowing, called a urethral stricture . The location and structure of the narrowing can be investigated with a medical imaging scan in which dye is injected through

385-449: Is a fibrous and muscular tube which connects the urinary bladder to the external urethral meatus . Its length differs between the sexes, because it passes through the penis in males. In the human male, the urethra is on average 18 to 20 centimeters (7 to 8 inches) long and opens at the end of the external urethral meatus. The urethra is divided into four parts in men, named after the location: These openings are collectively called

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420-435: Is obliquely downward and forward; it is slightly curved with the concavity directed forward. The proximal two-thirds of the urethra is lined by transitional epithelial cells , while the distal third is lined by stratified squamous epithelial cells . Between the superior and inferior fascia of the urogenital diaphragm , the female urethra is surrounded by the urethral sphincter . The urethra in female placental mammals

455-419: Is removed before ejaculation by pre-ejaculate fluid – called Cowper's fluid – from the bulbourethral gland. Infection of the urethra is urethritis , which often causes purulent urethral discharge. It is most often due to a sexually transmitted infection such as gonorrhoea or chlamydia , and less commonly due to other bacteria such as ureaplasma or mycoplasma ; trichomonas vaginalis ; or

490-577: 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

525-410: Is typically longer than in females. In the human female, the urethra is about 4 cm long, having 6 mm diameter, and exits the body between the clitoris and the vaginal opening , extending from the internal to the external urethral orifice . The meatus is located below the clitoris. It is placed behind the symphysis pubis , embedded in the anterior wall of the vagina, and its direction

560-450: Is typically shorter than in the male. The cells lining the urethra (the epithelium ) start off as transitional cells as it exits the bladder, which are variable layers of flat to cuboidal cells that change shape depending on whether they are compressed by the contents of the urethra. Further along the urethra there are pseudostratified columnar and stratified columnar epithelia. The lining becomes multiple layers of flat cells near

595-499: 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

630-455: 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

665-422: 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

700-408: The external urethral sphincter is supplied by the pudendal nerve . In the developing embryo , at the hind end lies a cloaca . This, over the fourth to the seventh week, divides into a urogenital sinus and the beginnings of the anal canal , with a wall forming between these two inpouchings called the urorectal septum . The urogenital sinus divides into three parts, with the middle part forming

735-402: 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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770-801: 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 ,

805-403: The biological sex of the embryo. In the male, the epithelium multiples to form the prostate . In the female, the upper part of the urethra forms the urethra and paraurethral glands . The urethra is the vessel through which urine passes after leaving the bladder. During urination, the smooth muscle lining the urethra relaxes in concert with bladder contraction(s) to forcefully expel the urine in

840-478: 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

875-402: The cucumber. At night, many of these species emerge through the anus of the sea cucumber in search of food. Urethra The urethra ( pl. : urethras or urethrae ) is the tube that connects the urinary bladder to the urinary meatus , through which placental mammals urinate and ejaculate . In non-mammalian vertebrates , the urethra also transports semen but is separate from

910-399: The end of the urethra, which is the same as the external skin around it. There are small mucus -secreting urethral glands, as well as bulbo-urethral glands of Cowper, that secrete mucous acting to lubricate the urethra. The urethra consists of three coats: muscular, erectile, and mucous, the muscular layer being a continuation of that of the bladder. Somatic (conscious) innervation of

945-422: The infection is treated, so that they do not spread the infection to others. Because of this spread, which may occur during an incubation period before a person gets symptoms, there is often contact tracing so that sexual partners of an affected person can be found and treatment offered. Cancer can also develop in the lining of the urethra. When cancer is present, the most common symptom in an affected person

980-450: The time it was called "ureter". Thereafter, terms "ureter" and "urethra" were variably used to refer to each other thereafter for more than a millennia. It was only in the 1550s that anatomists such as Bartolomeo Eustacchio and Jacques Dubois began to use the terms to specifically and consistently refer to what is in modern English called the ureter and the urethra. Following this, in the 19th and 20th centuries, multiple terms relating to

1015-497: The urethra. In addition, the closing mechanisms of the urethra, together with immunoglobulins , largely prevent germs from penetrating the inside of the body. In marsupials , the female's urethra empties into the urogenital sinus . The word "urethra" comes from the Ancient Greek οὐρήθρα – ourḗthrā . The stem "uro" relating to urination, with the structure described as early as the time of Hippocrates . Confusingly however, at

1050-414: The urethra; the upper part is largest and becomes the urinary bladder , and the lower part then changes depending on the biological sex of the embryo. The cells lining the urethra (the epithelium) come from endoderm , whereas the connective tissue and smooth muscle parts are derived from mesoderm . After the third month, urethra also contributes to the development of associated structures depending on

1085-401: The urinary meatus into the urethra, called a retrograde urethrogram . Additional forms of imaging, such as ultrasound , computed tomography and magnetic resonance imaging may also be used to provide further details. Injuries to the urethra (e.g., from a pelvic fracture ) Foreign bodies in the urethra are uncommon, but there have been medical case reports of self-inflicted injuries,

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1120-401: The urinary tract. The external urethral sphincter is a striated muscle that allows voluntary control over urination. The internal sphincter , formed by the involuntary smooth muscles lining the bladder neck and urethra, receives its nerve supply by the sympathetic division of the autonomic nervous system . The internal sphincter is present both in males and females. The urethra

1155-451: The verumontanum (colliculus seminalis). The prostatic urethra is a common site of obstruction to outflow of urine in BPH patients Stratified squamous – distally There is inadequate data for the typical length of the male urethra; however, a study of 109 men showed an average length of 22.3 cm (SD = 2.4 cm), ranging from 15 cm to 29 cm. The urethra in male placental mammals

1190-474: The viruses herpes simplex virus and adenovirus . Investigations such as a gram stain of the discharge might reveal the cause; nucleic acid testing based on the first urine sample passed in a day , or a swab of the urethra sent for bacterial culture and sensitivity may also be used. Treatment usually involves antibiotics that treat both gonorrhoea and chlamydia, as these often occur together. A person being treated for urethritis should not have sex until

1225-431: 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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