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Urinary system

8-minute read

Key facts

  • Your urinary system, also called the renal system or urinary tract, removes waste from your blood, in the form of urine.
  • It also helps regulate your blood volume and pressure and controls the level of chemicals and salts (electrolytes) in your body's cells and blood. 
  • Common medical problems with the urinary system include infections, kidney stones, urinary retention and urinary incontinence.
  • If you experience problems or changes in your urinary frequency or flow, see your doctor.
  • You can help keep your urinary system healthy by drinking enough water, avoiding smoking and maintaining a healthy lifestyle.

What is the urinary system?

Your urinary system prevents waste and toxins from building up in your blood. It also:

  • controls the levels of chemicals and salts in your blood
  • maintains your body's water balance
  • helps regulate your blood pressure
  • maintains vitamin D production to help keep bonesstrong and healthy
  • helps make your body's red blood cells

What are the different parts of the urinary system?

Your urinary system is made up of:

  • 2 kidneys — body organs that filter blood to make urine
  • the bladder — an organ for storing urine
  • 2 ureters — tubes connecting your kidneys to your bladder
  • the urethra — a tube connecting your bladder to your body's surface

How does the urinary system work?

Your kidneys work non-stop, filtering all of your blood passing through them every 5 minutes.

The urine that collects is a mix of waste and excess fluid. It is carried to your bladder to be stored. Muscles in the bladder wall stay relaxed, so it can expand as it fills. Other muscles work like a dam to keep urine in your bladder until you are ready to go to the toilet. Your brain controls your bladder, signalling it when to hold urine and when to empty. Urinary incontinence is when there is accidental or involuntary loss of urine from the bladder.

To urinate normally, all parts of your urinary tract must work together in proper order.

When you are ready to go to the toilet, your bladder outlet muscles (urethral sphincter and pelvic floor) relax and your bladder wall muscles contract. Urine empties from your bladder through your urethra and leaves your body.

What are some common medical conditions related to the urinary tract?

Urinary tract infection

Urinary tract infections (UTIs) occur when an infection, usually caused by bacteria, enters the urinary tract. The most common types of UTI include:

  • cystitis, an infection of the bladder lining, and the most common lower urinary tract infection
  • urethritis, an infection of the urethra
  • pyelonephritis, an infection of the upper urinary tract, which canbe very serious because it affects the kidneys

See your doctor if you have symptoms of a UTI.

Learn more about urinary tract infections, causes, risks, treatment and prevention.

Kidney stones

Kidney stones develop when waste chemicals in your urine form crystals that clump together. They can cause severe pain. It is important to see your doctor if you think you might have a kidney stone.

Learn more about kidney stones and how to prevent them.

Urinary retention

Urinary retention, is being unable to empty your bladder. It can be acute or chronic (short or long term).

If you can't pass urine even though you feel the need to, and your bladder is full, this is acute urinary retention. If you feel you might have urinary retention, see your doctor, visit a medical centre urgently, or go to your nearest emergency department.

People with chronic urinary retention can urinate, but do not completely empty the urine from their bladders. This can be a slow-developing and long-lasting medical condition.

Learn more about urinary retention, its types, causes and complications.

Urinary incontinence

Urinary incontinence is when you have trouble controlling your bladder. You may experience accidental or involuntary loss of urine from the bladder. It is very common, and can be distressing, but is usually treatable.

Learn more about urinary incontinence, types, tips and treatment.

Prostate problems

In males, the urethra passes through the prostate gland. Because of this, swelling or enlargement of this gland can affect the flow of urine through the urethra. Problems with urinary flow is one of the most common signs of possible prostate problems.

Learn more about prostate problems and looking after yourself to reduce symptoms.

When should I see my doctor?

You should see your doctor if you have symptoms of problems with your urinary system.

Symptoms of bladder problems can include:

Many people with kidney disease don't notice any symptoms in the early stages.

Some people with kidney disease may experience:

  • changes in the amount of urine passed
  • changes in their urine's appearance (for example, frothy or discoloured urine)
  • blood in the urine
  • pain in the abdomen or back
  • leg swelling
  • fatigue
  • loss of appetite

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

If you're at risk of kidney disease, for example, because of diabetes, high blood pressure or smoking, you should see your doctor for a kidney health check at least every 2 years. A kidney health check usually includes a blood pressure check and blood tests, to make sure your kidneys are working well.

ARE YOU AT RISK? — Are you at risk of type 2 diabetes, heart disease or kidney disease? Use the Risk Checker to find out.

How can I look after my urinary system?

Here are some tips to ensure your urinary system stays healthy, and how to notice any potential problems early:

Resources and support

  • The Continence Foundation of Australia provides information and support, and can help you find out more about continence and bladder health. You can also call the National Continence Helpline on 1800 33 00 66 for confidential information and advice.
  • The Kidney Health Australia website has information about kidney health and conditions. You can also call the Kidney Helpline on 1800 454 363 for information and advice.
  • Your GP can refer you to a renal dietitian, and the Dietitians Association of Australia can provide names and contact details of local renal dietitians. You can also call the dietitians Association of Australia on 1800 812 942 for information on where to find a renal dietitian.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: March 2023

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