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The urinary system

The urinary system is a group of organs responsible for the elimination of bodily waste among other important functions. Below is a brief introduction to the system, and its main components.

The urinary system in brief

The main purpose of the urinary system, also known as the urinary tract, is to eliminate waste from the body through the excretion of urine. The system also handles other important functions such as the regulation of blood pressure and volume, controlling of electrolyte and metabolite levels and regulation of blood acidity. If you experience problems passing urine or symptoms of urinary tract obstructions, you should always consult your doctor for a medical examination.

NB! Please note that the information on this site is meant as a general introduction to the urinary system and should not be considered exhaustive or complete.

The Kidneys

The kidneys consist of two organs positioned on either side of the spine. The kidneys’ shape resembles a bean, and are roughly the size of a large adult fist. Their function is to filter wastes from the blood and excrete it through the urine. In addition, the kidneys are responsible for controlling the body’s fluid balance and maintain the correct levels of electrolytes. The body’s entire supply of blood passes through the kidneys several times every day.

The Ureters

The ureters are two tubes made of smooth muscle fibers connecting the kidneys to the urinary bladder. In adults, the ureters are typically 25-30 cm. long and 3-4 mm. in diameter. Their function is to carry urine from the kidneys to the urine bladder. As a cause of illness or trauma the ureters can in some cases become obstructed. Ureteric stricture can vary in severity and may require treatment in the form of e.g. pharmaceuticals, surgery or medical devices.

The Urinary Bladder

The urinary bladder is a hollow organ made of stretchable muscular fibers positioned just above the pubic bone. When empty, the bladder’s shape and size resemble a pear. When full it can contain up 600 mL of urine. The bladder’s function is to store urine allowing the body to urinate infrequently and controlled by use of the bladder muscle. In some cases, e.g. as a side-effect to surgery, the bladder neck may become obstructed. This is knowns as Bladder neck stricture.

The Prostate

The prostate, which is only present in the male body, is a walnut-sized gland situated between the bladder and the penis. The urine flows via the urethra through the center of the prostate, from the bladder to the penis, and thereby out the body. Its function is to secrete fluid during ejaculation that nourishes and protects sperm. The prostate is susceptible to conditions such as prostatic obstruction caused by benign prostatic enlargement or prostate cancer.

The Urethras

Like the ureters, the urethra is the tube made from muscle fibers. The urethra is the lower-most part of the urinary system which connects the urinary bladder to the meatus called the penis in men and the vagina in women. The function of the urethra is to carry the urine stored in the urinary bladder and out of the body. As causes of illness or trauma the urethra is susceptible to obstructions known bulbar urethral stricture and penile urethral stricture.

Symptoms of urinary tract obstructions

Urinary tract obstruction is a blockage in the urinary tract hindering the flow of urine. Obstructions of the urinary tract can be partial or complete, and can arise as cause of e.g. illness, trauma or surgery side-effects. Urinary tract obstructions can result in pain, infections, kidney failure and in severe cases even death. If urinary tract obstruction is suspected, it is out most important to consult a doctor for a medical examination. Examples of common urinary tract obstruction symptoms are

  • Difficulty in starting urination
  • Interrupted and/or weak urinary stream
  • Continuous feeling of having a full bladder
  • Inability to empty the bladder completely
  • Frequent urination especially at night
  • Blood in the urine
  • Flank pain