The excretion of end products of the body’s metabolism, within which the urine or urine in particular has a central role, is based on anatomically different structures. They not only collect and filter the urine, but also pass it on to the final excretion stage. The urethra makes an important contribution in this context.
What is the urethra?
Schematic diagram showing the anatomy and structure of the urinary bladder. Click to enlarge. The urethra or urethra is one of the organs that drain urine and therefore consists of extremely complicated anatomical structures. The urethra is only one section that makes up the entire urinary tract, such as the renal calices, the renal pelvis, and the urinary bladder and ureters. The urinary bladder is present in both women and men and performs additional tasks depending on gender. In this regard, the urethra in men carries not only urine, but also seminal fluid. Differences between the layout of the urethra in women and men can also be seen in its length.
Anatomy and structure
Due to the anatomy of the urethra, it appears in cross-section as a hollow tube. This is lined with various tissue areas that lie one on top of the other in layers. These tissues include both muscular areas and areas interspersed with mucous cells. In anatomy, these have been given the name epithelium, or more precisely urothelium. The urethra also contains a tightly branched network of blood vessels and nerves. Of particular importance is the “construction” of the male urethra, which has a higher muscular content than the female urethra. From the anatomical position, the beginning of the urethra is located directly at the exit of the urinary bladder. In addition, so-called narrow and branching points can be identified in the male urethra. The female urethra has its orifice between the vagina and the vaginal vestibule. Since the female urethra also contains muscle tissue, but not as strong as in men, the urethra can nevertheless support limited urination when contracted.
Functions and tasks
In explaining the function of the urethra, a differentiated approach must be taken because it differs in women and men. Nevertheless, the emptying process performed by the urethra is subject to the same processes. The physiological condition of the urethra is represented by complicated processes, which are carried out one after the other like a chain. The starting point of these chain processes is taken by the filled urinary bladder, which sends an impulse via the ingrown nerves to the responsible brain areas. An increase in pressure on the inner walls of the urinary bladder causes overstretching of the elastic urinary bladder wall tissues. A signal from the brain allows the urinary bladder to contract as it progresses. The sphincter muscle in the lower zone of the urinary bladder opens and urine flows out through the urethra in a voluntary controlled manner. At the same time, the urethra also contracts and the urine is forced out, under more or less pressure, so that a stream is formed.
Diseases
The urethra has a very significant influence on the excretion of urine and can promote incontinence in the presence of organic restrictions. Most people are affected by an inflammation of the urethra known as urethritis during their lifetime. These inflammations are usually caused by bacteria or fungi that enter the urethra either from the outside or through the kidneys. In addition, a disease of the urethra with many risks is cancer of the urethra, which can develop through tumor growth. Other diseases which can be diagnosed in the urethra are atresia of the urethra, in which no urethra is created. In contrast, there is a growth of multiple urethras. Congenital megaloutrea includes massive enlargement of the urethra and is associated with a noticeable curvature of the penis. Equally important are an abnormal shape of the penis due to an abnormal exit of the urethra and meatus narrowing. Other diseases of the urethra may result from mechanical action in the form of injuries. Worth mentioning are stress or stress incontinence, which occurs primarily in women, likewise meatus stenosis and caruncle in the urethra.In urethral caruncle, there is a prolapse of the urethra into the female reproductive organs. Diverticula due to changes in the urethral glands and fistulas in the urethra are also significant.
Typical and common diseases
- Incontinence (urinary incontinence)
- Urethritis (inflammation of the urethra)
- Cancer of the urethra (less common)
- Urethral stricture
- Frequent urination
