Urethra is an opening that allows the urine to discharge from the Urinary Bladder. It is due to the existence of Urethra tube that we pass out Urine from our body. Urethra is a tube that connects the Bladder to the Genitals and Genitals discharge the Urine.The transport tube leading from the bladder to discharge urine outside the body. In males, the urethra travels through the penis, and carries semen as well as urine. In females, the urethra is shorter than in the male and emerges above the vaginal opening.
What is Urethral Stricture?
Urethral stricture refers to any narrowing of the urethra for any reason whether or not it actually impacts the flow of urine out of the bladder.
Any inflammation of urethra can result in scarring, which then can lead to a stricture or a narrowing of the urethra. Trauma, infection, tumors, surgeries, or any other cause of scarring may lead to urethral narrowing or stricture. Mechanical narrowing of the urethra without scar formation (developmental causes or prostate enlargement) can also cause urethral stricture.
Urethral stricture is significantly more common in men and boys compared to women and girls. This condition is considered rare in females.
The female urethra is about 1.5 to 2 (about 35 mm) inches long. It is located posterior to the pubic symphysis and is situated in the front wall of the vagina. The urethra is slightly curved and is directed in the forward direction. It is a membranous canal made up of the following three layers:
- Muscular layer – this is the continuation of the muscular layer of the urinary bladder.
- Mucous layer – this layer is also continuous with that of the bladder. It is lined with laminated epithelium.
- Spongy erectile tissues – It is a thin layer that is made up of the spongy epithelial tissues, which includes plexus of veins and smooth muscle fibers.
The urethra is surrounded by the urethral sphincter, which gets its supply from the pudendal nerve. The female urethra ends at the external orifice of urethra. The structure of the female urethra is simpler than that of the male urethra, for the fact that female urethra carries only urine, unlike the male urethra which is designed to carry both urine and semen.
The male urethra is 8 to 9 inches (200mm) long. It is in the shape of a tube. Its prostatic section is arched in shape. The male urethra is longer than the female one, as it has an additional reproductive function to perform along with the excretion of urine. It is concerned with the conveyance of semen out of the body at the time of ejaculation.
The male urethra is divided into three parts:
- The Prostatic urethra – The prostatic part of the urethra is the widest and the most dilatable part of the urethra that begins at the neck of the bladder and continues through the prostrate gland.
- Membranous urethra – this is the shortest and a very narrow part of the male urethra. It passes through the urogenital diaphragm. It is here that the sphincter is located that controls the storage and expulsion of urine from the bladder.
- Spongy urethra – it is the longest of the three sections, being approximately 6 inches in length. It extends from the end of the membranous portion, continuous through the penis and ends at the external orifice of the urethra. At this point, the urine leaves the body.
The ejaculation of semen takes place from the urethra itself, and this is the reason that the structure of the male urethra is more complicated than the female one.
Causes, Incidence And Risk Factors:
Urethral stricture may be caused by inflammation or scar tissue from surgery, disease, or injury. It may also be caused by pressure from an enlarging tumor near the urethra, although this is rare.
Other risks include:
- A history of sexually transmitted disease (STD)
- Any instrument inserted into the urethra (such as a catheter or cystoscope)
- Benign prostatic hyperplasia (BPH)
- Injury or trauma to the pelvic area
- Repeated episodes of urethritis
Strictures that are present at birth (congenital) are rare. Strictures in women are also rare. There are several causes of urethra inflammation in women. The most common of these are the sexually transmitted diseases Chlamydia, gonorrhea, syphilis, and HIV/AIDS.
- Blood in the semen
- Bloody or dark urine
- Decreased urine output
- Difficulty urinating
- Discharge from the urethra
- Frequent or urgent urination
- Inability to urinate (urinary retention)
- Painful urination (dysuria)
- Pain in the lower abdomen
- Pelvic pain
- Slow urine stream (may develop suddenly or gradually)
- Spraying of urine stream
- Swelling of the penis
Signs And Tests:
A physical examination may show the following:
- Decreased urinary stream
- Discharge from the urethra
- Enlarged (distended) bladder
- Enlarged or tender lymph nodes in the groin (inguinal) area
- Enlarged or tender prostate
- Hardness (induration) on the under surface of the penis
- Redness or swelling of the penis
Sometimes the exam reveals no abnormalities.
Tests include the following:
- Post-void residual (PVR) volume
- Retrograde urethrogram
- Tests for chlamydia and gonorrhea
- Urinary flow rate
- Urine culture
The key function of Urethra is to expel the Urine. This seems to be an easy function but it needs a lot of effort.
The Levator Ani muscle in the Pelvic area controls the Urination in the Humans. This muscle is a very weak muscle and it can be damaged at the time of Childbirth.
The Male Urethra is longer than the female Urethra. At the time of Ejaculation, this provides the route of Semen along with the Urine. This is the reason the Male Urethra passes through the Prostate Gland.
Urethra and Ureter:
The ureter is a tube which connects the kidney to the bladder so as to allow the transportation of urine from the kidney to the bladder. The urethra connects the bladder to the genitals. Both these ducts are concerned with the transportation of urine.