The urethra 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 the urinary tract.
The bladder is a hollow organ in humans and other vertebrates that stores urine from the kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. 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 prostate is an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemically, and physiologically. Anatomically, the prostate is found below the bladder, with the urethra passing through it. It is described in gross anatomy as consisting of lobes and in microanatomy by zone. It is surrounded by an elastic, fibromuscular capsule and contains glandular tissue, as well as connective tissue.
The navel is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord.
The seminal vesicles are a pair of convoluted tubular accessory glands that lie behind the urinary bladder of male mammals. They secrete fluid that largely composes the semen.
The urogenital sinus is a body part of a human or other placental only present in the development of the urinary and reproductive organs. It is the ventral part of the cloaca, formed after the cloaca separates from the anal canal during the fourth to seventh weeks of development.
A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the vitelline duct. It is the most common malformation of the gastrointestinal tract and is present in approximately 2% of the population, with males more frequently experiencing symptoms.
The allantois is one the extraembryonic membranes arising from the yolk sac. It is a hollow sac-like structure filled with clear fluid that forms part of the developing conceptus in an amniote that helps the embryo exchange gases and handle liquid waste. The other extraembryonoic membranes are the yolk sac, the amnion, and the chorion. In mammals these membranes are known as fetal membranes.
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.
The development of the urinary system begins during prenatal development, and relates to the development of the urogenital system – both the organs of the urinary system and the sex organs of the reproductive system. The development continues as a part of sexual differentiation.
In human anatomy, the median umbilical ligament is an unpaired midline ligamentous structure upon the lower inner surface of the anterior abdominal wall. It is covered by the median umbilical fold.
A urachal cyst is a sinus remaining from the allantois during embryogenesis. It is a cyst which occurs in the remnants between the umbilicus and bladder. This is a type of cyst occurring in a persistent portion of the urachus, presenting as an extraperitoneal mass in the umbilical region. It is characterized by abdominal pain, and fever if infected. It may rupture, leading to peritonitis, or it may drain through the umbilicus. Urachal cysts are usually silent clinically until infection, calculi or adenocarcinoma develop.
The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typically described together as the genitourinary system.
Urachal cancer is a very rare type of cancer arising from the urachus or its remnants. The disease might arise from metaplastic glandular epithelium or embryonic epithelial remnants originating from the cloaca region.
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.
Diphallia, penile duplication (PD), diphallic terata, or diphallasparatus is an extremely rare developmental abnormality in which a male is born with two penises. The first reported case was by Johannes Jacob Wecker in 1609. Its occurrence is 1 in 5.5 million boys in the United States.
A urethral diverticulum is a condition where the urethra or the periurethral glands push into the connective tissue layers (fascia) that surround it.
A urachal fistula is a congenital disorder caused by the persistence of the allantois, the structure that connects an embryo's bladder to the yolk sac. Normally, the urachus closes off to become the median umbilical ligament; however, if it remains open, urine can drain from the bladder to an opening by the umbilicus.
Umbilical-urachal sinus is a congenital disorder of the urinary bladder caused by failure of obliteration of proximal or distal part of the allantois, and the presentation of this anomaly is more common in children and rarer in adults. In contrast to a urachal diverticulum, it is characterised by focal dilatation of the umbilical portion of the remnant urachal tract.
A urachal diverticulum is a congenital disorder caused by the partial persistence of the allantois. The allantois, which later becomes the urachus, connects an embryo's bladder to the yolk sac. Normally, the urachus closes off to become the median umbilical ligament; however, if it does not seal close to the bladder, a blind pouch connected to the bladder remains. This is usually asymptomatic but can lead to recurrent urinary tract infections. If the urachus is wholly patent, urine can drain from the bladder to an opening by the umbilicus, a condition known as urachal fistula.
