Urinary System

The urinary system includes your kidneys, ureters, bladder and urethra. This system filters your blood, removing waste and excess water. This waste becomes pee. The most common urinary issues are bladder infections and urinary tract infections (UTIs).


Comparison of urinary system in males and females.
Your urinary system is your body's filtering system and produces your pee. The organs of the urinary system include kidneys, ureters, bladder and urethra.

What is the urinary system?

The urinary system (or urinary tract) works as your body’s filtration system. When your urinary system removes toxins and wastes from your body, it comes out as pee (urine). To be able to pee, your body must pass this waste through a series of organs, ducts and tubes. If there’s a problem at any step in this process, it can affect if you’re able to pee normally.

The main organs in your urinary system are:

  • Two kidneys (blood-filtering organs).
  • Two ureters (ducts that connect your kidneys to your bladder)
  • A bladder (an organ that holds your pee).
  • A urethra (a tube connected to your bladder that allows pee to leave your body).

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What is the main function of the urinary system?

Your urinary system filters your blood to get rid of what your body doesn’t need. It eliminates extra water and salt, toxins and other waste products. Different parts of the urinary system perform tasks, including:

  • Filtering blood.
  • Separating the toxins you don’t need from the nutrients you do need.
  • Storing and carrying pee out of your body.

How does the urinary system filter my blood?

Your kidneys are an essential part of filtering your blood. Here’s how the urinary system works:

  1. Your blood enters each kidney through lots of little arteries.
  2. Your kidneys filter your blood, separating toxins from nutrients.
  3. Vitamins, minerals, nutrients and proteins return back to your bloodstream.
  4. Waste products and pee move from your kidneys through your ureters and to your bladder.
  5. Your bladder stores your pee until you use the toilet.
  6. Pee leaves your body through your urethra.


What are the organs of the urinary system?

The kidneys, ureters, bladder and urethra make up the urinary system. They all work together to filter, store and remove liquid waste from your body. All of the organs in your urinary system are in your abdominal and pelvic region.

Here’s what each organ does:

  • Kidneys: These organs work constantly. They filter your blood and make pee, which your body then eliminates. You have two kidneys, one on either side of the back of your abdomen, just below your rib cage. Each kidney is about as big as your fist. Your kidneys work hard — they filter about 120 to 150 quarts (113.6 to 141.95 liters) of blood per day, which produces about 1 to 2 quarts (0.95 to 1.95 liters) of pee each day.
  • Ureters: These two thin tubes inside your pelvis carry pee from your kidneys to your bladder. Each ureter is about 9 inches long.
  • Bladder: Your bladder holds pee until you’re ready to empty it (pee). It’s hollow, made of muscle, and shaped like a triangular balloon. Your bladder expands as it fills up. Most bladders can hold up to 2 cups (500 milliliters) of pee at a time. Peeing is when you empty your bladder.
  • Urethra: This tube carries pee from your bladder out of your body. You have two sphincter muscles that close off your urethra to keep pee in when you aren’t using the toilet. These ring-like muscles open and close to let pee out. Sometimes, these muscles weaken and it becomes hard to hold your pee in.

Conditions and Disorders

What conditions and diseases affect the urinary system?

Many conditions can affect your ureters, kidneys, bladder and urethra. Infections, diseases or problems can appear at birth or develop as you get older. Cancer can also affect certain parts of your urinary tract.

Some common urinary disorders are:


Urinary tract infections and sexually transmitted infections (STIs) can cause issues with your kidneys, urethra or bladder. These infections occur when bacteria enter your urinary tract through your urethra. Your healthcare provider can prescribe medication (typically antibiotics) to treat an infection.

Kidney stones

Kidney stones are small masses that form when waste products clump together. Kidney stones or ureteral stones (kidney stones that move to your ureter) can cause severe pain and block the flow of pee.

Urination problems

Loss of bladder control or urinary incontinence (leakage), causes pee to leak when you don’t want it to. It can be worse when you cough, laugh, sneeze or jump. Overactive bladder happens when you feel the sudden urge to pee more often. Urinary retention is a condition where your bladder doesn’t completely empty each time.

Many of these conditions consist of lower urinary tract symptoms like an urge to pee, a weak urine stream and leaking pee. Medications and lifestyle modifications can help treat these conditions.

Urinary tract obstructions

Growths or tumors in any part of your urinary tract can affect the flow of pee. An enlarged prostate can block your ureter so it’s harder to pee. Other causes of ureteral obstruction include pregnancy and gastrointestinal (GI) issues like Crohn’s disease. Bladder outlet obstruction can also happen and prevent your bladder from emptying. Surgery can often help with obstructions in your urinary tract.

Kidney disease

Kidney disease is a common and serious condition that affects your urinary system. The most common causes of chronic kidney disease (CKD) are high blood pressure and diabetes. Managing blood pressure and blood sugar is crucial to lowering your risk of kidney disease. Kidney disease can lead to kidney failure. Kidney failure may require dialysis or a kidney transplant. Talk to your healthcare provider about your risk for kidney disease so you can take steps to lower your risk.

Interstitial cystitis

Also called painful bladder syndrome, this condition causes inflammation in your bladder. Medications and physical therapy can improve the symptoms of painful bladder syndrome.

Structural problems

Sometimes, babies are born with conditions that affect the way their urinary tract forms. For example, an ectopic ureter is when your child’s ureter connects to a place other than their bladder. Other urinary system organs can be underdeveloped, which can lead to issues with peeing.

A bladder prolapse is when your bladder drops into your vagina or hangs out of your vaginal opening. Sometimes surgery is required to fix the problem.

What are common symptoms of urinary tract conditions?

Symptoms vary depending on what condition you have. Many conditions share similar symptoms, like:

  • Changes in how you pee: This could include many different symptoms like having to pee more or less often and pain when you pee.
  • Changes in your pee: This may include pee that’s brown, cloudy or contains blood.
  • Pain in your abdominal region: Since most of your urinary organs are in your abdomen, people with urinary issues may have pain, tenderness or feel pressure in that region of their body.
  • Fever, muscle aches and general unwell feeling: These could all be symptoms that indicate infection. You may also experience nausea or vomiting.

What tests can check for urinary system conditions?

The tests your healthcare provider will order to diagnose a condition affecting your urinary system depend on your symptoms and other factors. Some tests you may need to have include:

  • Urinalysis: A urinalysis (also known as a urine test) is a test that examines the color, appearance, chemical and microscopic aspects of your pee.
  • Kidney functioning test: This test measures how well your kidneys are working. It can involve both a blood test and a urine test.
  • Blood tests: Blood tests can give healthcare providers clues as to what’s going on inside your body. Blood tests show what types of chemicals, proteins and other substances are in your blood.
  • Urethral swab: Also called a urethral discharge test, this test involves collecting a sample of discharge from your urethra for testing.
  • Urine culture: This type of test involves growing bacteria from a urine sample. Your provider may order this test after they diagnose a UTI. This helps them pinpoint exactly what bacteria caused the UTI.
  • Imaging tests: Your provider may order imaging tests to diagnose certain conditions. These include ultrasound, X-ray, MRI (magnetic resonance imaging) and CT (computed tomography) scan.

What’s the most common urinary system problem?

The most common urinary issues are urinary tract infections (UTIs). More than 60% of women and people assigned female at birth (AFAB) will get at least one UTI in their lifetime.

More than half of people who’ve given birth will experience urinary incontinence in their lifetime, usually due to their pelvic floor muscles stretching.

Kidney stones are also fairly common, occurring in about 1 in every 10 people.

About 37 million people in the United States are living with chronic kidney disease.


How can I keep my urinary system healthy?

You can try to keep your urinary system healthy with proper hygiene and a healthy lifestyle. To help your urinary system work the way it should, you can:

  • Drink plenty of water: Staying hydrated will flush out your system and can help you prevent kidney stones and UTIs.
  • Eat a balanced diet: Low-sodium, high-calcium foods may prevent kidney stones.
  • Empty your bladder fully: Make sure you let all of your pee out when you use the toilet. Don’t hold pee in for long periods of time.
  • Wipe the right way: If you have a vagina, you should always wipe front to back after using the toilet. Proper wiping reduces the risk of bacteria getting into your vagina and causing a UTI.
  • Empty your bladder after sex: If you have a vagina, you should use the bathroom after having sex. Peeing promptly can clear out bacteria and reduce your risk of a UTI.
  • Practice safe sex: Protect yourself from sexually transmitted infections with a condom.
  • Do pelvic floor exercises: Also called Kegel exercises, these can reduce your risk of urinary incontinence by strengthening the muscles in your pelvic floor.
  • Keep your genital area clean: Use mild soap and water to clean your genitals and try to bathe or shower daily. Wear comfortable, loose underwear.

When should I call my doctor if I think I might have a problem with my urinary tract?

You should contact your healthcare provider if you’re having trouble or pain when you pee. It may be a sign of an infection or another condition. Call your provider if you have:

  • Blood in your pee (hematuria).
  • Burning sensation, pain or difficulty peeing.
  • Pain in your pelvic area, lower back, genital area or flank (the back and sides of your abdomen).
  • Trouble holding your pee or problems with leaking pee.
  • A feeling that something is bulging out of your vagina.

A note from Cleveland Clinic

Your urinary system plays a critical role in keeping you alive. It filters your blood and removes waste and excess water through your pee. Your urinary system includes your kidneys, ureters, bladder and urethra. Conditions like urinary tract infections (UTIs), sexually transmitted infections (STIs), kidney diseases and urinary tract obstruction can affect the health of your urinary system. If you have one of these conditions, talk to your healthcare provider about steps you can take to stay healthy.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 06/13/2023.

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