What is the urethra?
Through the urethra, urine produced in the kidneys and collected in the urinary bladder is released to the outside. Female and male urethra have differences.
Urethra – female: The female urethra is three to five centimeters long and has a star-shaped cross-section caused by folds. It begins at the lower end of the urinary bladder, called the bladder neck.
The structure of the urethral wall is three-layered:
- Inside it is lined with a covering tissue (epithelium) called urothelium.
- The next layer consists of smooth and striated muscles associated with the bladder muscles as well as the pelvic floor muscles.
- The outermost layer consists of loose connective tissue (tunica adventitia). It anchors the urethra in its environment. In addition, blood vessels and nerves run in it.
Beneath the mucous membrane of the female urethra is a tumescent venous plexus. This can press the longitudinal folds of the urethral mucosa against each other and thus contribute to the closure.
Urethra – male: The male urethra is about 20 centimeters long. It also serves as a seminal duct, as the semen draining pathways enter. Therefore, the male urethra is also called the urethral spermatic duct.
It is divided into four sections, whose names correspond to their anatomical location:
- Pars prostatica
- Pars membranacea
- Pars spongiosa
In contrast to the almost completely straight female urethra, the male urethra has two curvatures due to its incorporation into the penis. For the same reason, three constrictions are found in its course.
The excretory ducts of the prostate and seminal vesicles open into the pars prostatica. From here on, the male urethra is a part of the reproductive system.
In the part of the urethra that lies in the penis, several pea-sized mucous glands are found. Their secretion is weakly alkaline and is released before ejaculation. This neutralizes the acidic environment.
Otherwise, the wall structure of the male urethra largely corresponds to that of the female urethra.
Urinary tract (female and male)
The renal pelvis, ureter, urinary bladder and urethra together form the efferent urinary tract. Man and woman do not differ in this point. Urine formed in the kidneys leaves the body through the urinary tract.
What is the function of the urethra?
The urethra carries urine from the urinary bladder to the outside. In women, this is also the only function.
Where is the urethra located?
The exact location of the urethra varies in women and men.
Urethra – female:
The upper part of the female urethra lies within the wall of the urinary bladder and is called the pars intramuralis (as in the male). It then traverses the pelvic floor, passing anteriorly between the pubic symphysis and the anterior wall of the vagina.
The external opening of the urethra (ostium urethrae externum) is located between the labia minora, just below the clitoris and thus anterior to the vaginal entrance.
Urethra – Male:
Like the female urethra, the male urethra originates at the neck of the bladder. First, as pars intramuralis, it passes through the muscular wall of the urinary bladder and its internal sphincter.
Then, as the pars prostatica, it passes through the prostate gland. There the excretory ducts of the prostate gland and the seminal vesicle open into the urethra.
As the pars membranacea, the urethra runs through the male pelvic floor and is firmly integrated into the connective tissue of the pelvis in this area.
The last and, at around 15 centimeters, longest section of the male urethra is called the pars spongiosa. It runs through the erectile tissue of the penis and opens outward at the glans penis.
What problems can the urethra cause?
There are many different, mostly congenital malformations affecting the urethra. These are often associated with urinary outflow obstructions or malformations of the urethra.
Accidents (such as a traffic accident) can cause the urethra to tear or completely break off.
Cancers of the urethra also occur: Urethra carcinoma is a rare type of cancer that mainly affects women over the age of 50.
In all urethral problems, there is either difficulty in holding urine (urinary incontinence) or difficult or completely impossible urination (urinary retention). In the latter case, a catheter must be placed immediately to relieve the urinary bladder.
