A narrow, somewhat muscular tube that carries URINE from the BLADDER to the outside of the body. The point of exit is the urinary or urethral meatus. The urethral sphincter MUSCLE at the base of the bladder controls the release of urine into the urethra. Once the urethral sphincter relaxes to let urine pass, the urine flows to the outside of the body until the bladder empties and the urethral sphincter tightens. It may take a few seconds after the sphincter closes for the residual urine in the urethra to make its way out the urethral opening. BLADDER CATHETERIZATION, CYSTOSCOPY, ureteroscopy, and intravesical therapies use the urethra to enter the urinary system (usually with sedation or ANESTHESIA, except catheterization).
In a woman the urethra is about an inch and a half long, extending from the base of the bladder to the external GENITALIA where it exits the body between the CLITORIS and the VAGINA. The urethra’s only role in a woman is to carry urine from the body. In a man the urethra is about eight inches long and extends from the base of the bladder to exit the body at the tip of the PENIS. As it exits the bladder in a man the urethra passes through the PROSTATE GLAND, which encircles the neck of the bladder. The male urethra also carries SPERM during EJACULATION. The VAS DEFERENS, the tube that carries SEMEN from the male reproductive organs, enters the urethra at the prostate gland. A valve at the base of the urethra directs the flow of either urine or semen through the urethra.
For further discussion of the urethra within the context of the urinary system’s structure and function please see the overview section “The Urinary System.”
Resource: Facts On File Encyclopedia Of Health And Medicine
At birth the structures of the urinary system are fully developed and function under the automatic control of the NERVOUS SYSTEM. The newborn’s KIDNEYS filter BLOOD and make URINE. The BLADDER collects the urine and, when it fills to a point that triggers the micturition REFLEX, it empties to drain urine via the URETHRA to outside the body. Voluntary
Excessive excretion of ALBUMIN, a form of protein, into the URINE. Albuminuria, also called proteinuria, typically indicates kidney conditions that affect the glomeruli (the tubular structures within the KIDNEYS that filter wastes and excess water from the BLOOD to excrete in the urine). Such conditions include GLOMERULONEPHRITIS, GLOMERULOSCLEROSIS,
What is Alport’s Syndrome An inherited genetic disorder in which one, two, or three mutations occur in the GENE that encodes type IV collagen formations, also called basement membranes. The mutations affect up to three of the six protein chains (alpha-3, alpha-4, and alpha-5) that make up type IV collagen, which is a foundation for a number of
What is Anuria and Definition Anuria - The failure to produce URINE. Numerous circumstances can result in anuria, from severe DEHYDRATION and severe HYPOTENSION (low BLOOD PRESSURE) to END-STAGE RENAL DISEASE (ESRD) and RENAL FAILURE. Anuria requires prompt medical evaluation to determine and remedy the underlying cause. Without such correction, waste
What is Bladder and Definition A muscular, saclike structure in the lower pelvis that serves as a reservoir for the URINE the KIDNEYS produce. In women the bladder is in front of and slightly below the UTERUS. During PREGNANCY the expanding uterus limits the bladder’s ability to expand, accounting for the URINARY FREQUENCY common in pregnancy’s
What is Uremia and Definition Uremia is a serious condition in which nitrogenbased toxins such as urea and creatinine, the primary waste products of METABOLISM, accumulate in the BLOOD because the KIDNEYS are unable to filter them out and pass them from the body via the URINE. Uremia indicates RENAL FAILURE. Urologists sometimes use the term azotemia to
Ureter, in a human organism, is a muscular tube, fairly thick and rigid, that leads URINE from the kidney to the urinary BLADDER. Both of the two tubular structures arise from the renal pelvis and collect the urine from the kidney’s collecting tubules. Both ureters with the inner diameter of 3 or 4 millimeters exit the kidney at the hilus. Then, the
A narrow, somewhat muscular tube that carries URINE from the BLADDER to the outside of the body. The point of exit is the urinary or urethral meatus. The urethral sphincter MUSCLE at the base of the bladder controls the release of urine into the urethra. Once the urethral sphincter relaxes to let urine pass, the urine flows to the outside of the body until
What is Urethral Stricture Narrowing of the URETHRA, impeding the passage of URINE from the BLADDER to the outside of the body. Urethral stricture may be congenital (present at birth) or acquired such as through scarring resulting from repeated URETHRITIS, BLADDER CATHETERIZATION, and other irritations to the urethra. BENIGN PROSTATIC HYPERPLASIA (BPH) and
What is Urethritis and Definition INFLAMMATION of an URETER. INFECTION, typically a sexually transmitted disease (STD), is the most common cause of urethritis though urethritis may occur as a result of inflammation or irritation from trauma such as occurs with BLADDER CATHETERIZATION or CYSTOSCOPY. Traumatic urethritis improves rapidly when the source of