The urethra is a tube that connects the mammalian urinary bladder to the urinary meatus. Male and female placental mammals release urine through the urethra during urination, but males also release semen through the urethra during ejaculation.
The bladder is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In placental mammals, urine enters the bladder via the ureters and exits via the urethra. In humans, the bladder is a distensible organ that sits on the pelvic floor. The typical adult human bladder will hold between 300 and 500 ml before the urge to empty occurs, but can hold considerably more.
The human urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. The urinary tract is the body's drainage system for the eventual removal of urine. The kidneys have an extensive blood supply via the renal arteries which leave the kidneys via the renal vein. Each kidney consists of functional units called nephrons. Following filtration of blood and further processing, wastes exit the kidney via the ureters, tubes made of smooth muscle fibres that propel urine towards the urinary bladder, where it is stored and subsequently expelled from the body by urination. The female and male urinary system are very similar, differing only in the length of the urethra.
Urinary incontinence (UI), also known as involuntary urination, is any uncontrolled leakage of urine. It is a common and distressing problem, which may have a large impact on quality of life. It has been identified as an important issue in geriatric health care. The term enuresis is often used to refer to urinary incontinence primarily in children, such as nocturnal enuresis. UI is an example of a stigmatized medical condition, which creates barriers to successful management and makes the problem worse. People may be too embarrassed to seek medical help, and attempt to self-manage the symptom in secrecy from others.
A urethral stricture is a narrowing of the urethra, the tube connected to the bladder that allows the passing of urine. The narrowing reduces the flow of urine and makes it more difficult or even painful to empty the bladder.
Dysuria refers to painful or uncomfortable urination.
In medicine or biology, a diverticulum is an outpouching of a hollow structure in the body. Depending upon which layers of the structure are involved, diverticula are described as being either true or false.
Feline lower urinary tract disease (FLUTD) is a generic category term to describe any disorder affecting the bladder or urethra of cats.
Hemorrhagic cystitis or haemorrhagic cystitis is an inflammation of the bladder defined by lower urinary tract symptoms that include dysuria, hematuria, and hemorrhage. The disease can occur as a complication of cyclophosphamide, ifosfamide and radiation therapy. In addition to hemorrhagic cystitis, temporary hematuria can also be seen in bladder infection or in children as a result of viral infection.
Posterior urethral valve (PUV) disorder is an obstructive developmental anomaly in the urethra and genitourinary system of male newborns. A posterior urethral valve is an obstructing membrane in the posterior male urethra as a result of abnormal in utero development. It is the most common cause of bladder outlet obstruction in male newborns. The disorder varies in degree, with mild cases presenting late due to milder symptoms. More severe cases can have renal and respiratory failure from lung underdevelopment as result of low amniotic fluid volumes, requiring intensive care and close monitoring. It occurs in about one in 8,000 babies.
Urethral cancer is a rare cancer originating from the urethra. The disease has been classified by the TNM staging system and the World Health Organization.
A urethrocele is the prolapse of the female urethra into the vagina. Weakening of the tissues that hold the urethra in place may cause it to protrude into the vagina. Urethroceles often occur with cystoceles. In this case, the term used is cystourethrocele.
Lower urinary tract symptoms (LUTS) refer to a group of clinical symptoms involving the bladder, urinary sphincter, urethra and, in men, the prostate. The term is more commonly applied to men – over 40% of older men are affected – but lower urinary tract symptoms also affect women. The condition is also termed prostatism in men, but LUTS is preferred.
Feline idiopathic cystitis (FIC) or feline interstitial cystitis or cystitis in cats, is one of the most frequently observed forms of feline lower urinary tract disease (FLUTD). Feline cystitis means "inflammation of the bladder in cats". The term idiopathic means unknown cause; however, certain behaviours have been known to aggravate the illness once it has been initiated. It can affect both males and females of any breed of cat. It is more commonly found in female cats; however, when males do exhibit cystitis, it is usually more dangerous.
Bladder outlet obstruction occurs when urine is unable to flow from the kidneys through the ureters and out of the bladder through the urethra. Decreased flow of urine leads to swelling of the urinary tract, called hydronephrosis. This process of decreased flow of urine through the urinary tract can begin as early as during intrauterine life and it prevents normal development of fetal kidneys and fetal urine. Low levels of fetal urine leads to low amniotic fluid levels and incomplete lung maturation. Older children and adults can also experience bladder outlet obstruction; however, this process is usually reversible and isn't associated with as many poor outcomes as in infants with congenital bladder outlet obstruction.
A Gartner's duct cyst is a benign vaginal cyst that originates from the Gartner's duct, which is a vestigial remnant of the mesonephric duct in females. Persistent Wolffian duct syndrome (PWDS) in individuals with XX chromosomes is the inverse disorder of Persistent Müllerian duct syndrome (PMDS) in individuals with XY chromosomes. They are typically small asymptomatic cysts that occur along the lateral walls of the vagina, following the course of the duct. They can present in adolescence with painful menstruation (dysmenorrhea) or difficulty inserting a tampon. They can also enlarge to substantial proportions and be mistaken for urethral diverticulum or cystocele. In some rare instances, they can be congenital.
A urethral bulking injection is a gynecological procedure and medical treatment used to treat involuntary leakage of urine: urinary incontinence in women. Injectional materials are used to control stress incontinence. Bulking agents are injected into the mucosa surrounding the bladder neck and proximal urethra. This reduces the diameter of the urethra and creates resistance to urine leakage. After the procedure, the pressure forcing the urine from the bladder through the urethra is resisted by the addition of the bulking agent in the tissue surrounding the proximal urethra. Most of the time this procedure prevents urinary stress incontinence in women.
If medical treatment is not effective, surgery may need to be performed for benign prostatic hyperplasia.
Vaginal cysts are uncommon benign cysts that develop in the vaginal wall. The type of epithelial tissue lining a cyst is used to classify these growths. They can be congenital. They can present in childhood and adulthood. The most common type is the squamous inclusion cyst. It develops within vaginal tissue present at the site of an episiotomy or other vaginal surgical sites. In most instances they do not cause symptoms and present with few or no complications. A vaginal cyst can develop on the surface of the vaginal epithelium or in deeper layers. Often, they are found by the woman herself and as an incidental finding during a routine pelvic examination. Vaginal cysts can mimic other structures that protrude from the vagina such as a rectocele and cystocele. Some cysts can be distinguished visually but most will need a biopsy to determine the type. Vaginal cysts can vary in size and can grow as large as 7 cm. Other cysts can be present on the vaginal wall though mostly these can be differentiated. Vaginal cysts can often be palpated (felt) by a clinician. Vaginal cysts are one type of vaginal mass, others include cancers and tumors. The prevalence of vaginal cysts is uncertain since many go unreported but it is estimated that 1 out of 200 women have a vaginal cyst. Vaginal cysts may initially be discovered during pregnancy and childbirth. These are then treated to provide an unobstructed delivery of the infant. Growths that originate from the urethra and other tissue can present as cysts of the vagina.
