An overview of the lower urinary tract1,2
Your urinary system includes an upper and lower tract, which work together to make, transport, store, and release urine from your body.2
- The upper urinary tract includes the kidneys and the ureters, which send urine from the kidneys into the bladder
- The lower urinary tract consists of the bladder and the urethra, a narrow tube that connects the bladder to the outside of your body
The bladder can store large volumes of urine. This is because the wall of the bladder is made up of smooth muscle tissue, which expands as the bladder fills and contracts to force urine out of the body. Two sphincters (rings of muscle) control the passage of urine during the urination process.
Common urinary tract conditions
Many conditions can affect the urinary system. Two of the most common problems affecting the lower urinary tract (bladder and urethra) are urinary tract infections (UTIs) and interstitial cystitis/painful bladder syndrome (IC/PBS). Certain kinds of diagnostic procedures can also cause painful or uncomfortable urinary symptoms.
A UTI is caused by the growth of bacteria in the urethra and bladder that has been transferred to the urinary tract from adjacent areas such as the digestive tract or vaginal system. If the bacteria are present only in the urethra, the infection is called urethritis. Bacterial infections that have spread into the bladder are called cystitis. If untreated, a lower UTI can also affect the kidneys, causing pyelonephritis (infection of the kidneys).UTIs are much more common in women than in men.3
UTIs can cause a variety of acute and uncomfortable symptoms, including4,5,6
- Painful, burning sensation in the bladder or urethra
- Frequent urge to urinate (even if urine volume is very small)
- Waking up at night to urinate
- Lower abdominal pressure or tenderness
(For more information, please see the UTI Fact Sheet.)
IC/PBS is a chronic condition that produces recurring pain and discomfort in the bladder and surrounding pelvic area. Its exact cause is unknown.7 Research has shown that IC/PBS may be triggered by bladder damage, causing the bladder to become irritated, sensitive, and inflamed.It affects many more women than men.7,8,9,10
The primary symptom of IC/PBS is pelvic pain or pressure that increases as the bladder fills and lessens once the bladder is emptied.Other symptoms of IC/PBS include7
- Frequent urination—as often as 10 to 50 times during a 24-hour period
- A persistent urge to urinate
- Waking up during the night to urinate
- Absence of urinary tract infection or other illness
(For more information, please see the IC/PBS Fact Sheet.)
Medical procedures involving special instruments that treat or diagnose urinary conditions can lead to an increased risk of UTI.11 These procedures include
- Urinary catheterization—a tube is inserted through the urethra into the bladder to drain and collect urine12
- Cystoscopy—a procedure involving the insertion of a thin, lighted tool (cystoscope) to view the urethra and inner bladder lining13
- Cystometry—a test that measures the pressure inside the bladder to assess how well is it functioning14
(For more information, please see the Diagnostic Procedures Fact Sheet.)
- Sherwood L, editor. Fundamentals of physiology: a human perspective. Belmont, CA: Brooks/Cole, Cengage Learning; 2006.
- National Kidney and Urologic Diseases Information Clearinghouse [Internet]. What is the urinary tract? [cited 2010 Jun 22]. Available from:http://kidney.niddk.nih.gov/kudiseases/pubs/imagingut/index.htm.
- Stamm WE. Harrison’s principles of internal medicine. 17th ed. New York, NY: McGraw Hill Medical; c2008. Urinary tract infections, pyelonephritis, and prostatitis; p. 1821-6.
- Rahn DD. Medscape [Internet]. Urinary tract infections: contemporary management [cited 2010 Jun 6]. Available from:http://www.medscape.com/viewarticle/583060.
- McPhee JS, Papadakis MA, editors. Current medical diagnosis and treatment. New York, NY: McGraw Hill Medical; c2009. p. 828,837-8.
- National Kidney and Urologic Diseases Information Clearinghouse [Internet]. Urinary tract infections in adults [cited 2010 Jun 22]. Available from: http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult/index.htm.
- Association of Reproductive Health Professionals [Internet]. Understanding interstitial cystitis/painful bladder syndrome [cited 2010 Jul 28]. Available from: http://www.arhp.org/Publications-and-Resources/Patient-Resources/fact-sh....
- National Kidney Foundation [Internet]. Interstitial cystitis [cited 2010 May 21]. Available from: http://www.kidney.org/atoz/content/interstitial.cfm.
- Interstitial Cystitis Association [Internet]. What is IC? [cited 2010 May 21]. Available from: http://www.ichelp.org/Page.aspx?pid=327.
- National Kidney and Urologic Diseases Information Clearinghouse [Internet]. Your urinary system and how it works [cited 2010 Jun 22]. Available from: http://kidney.niddk.nih.gov/kudiseases/pubs/yoururinary.
- Shankel S. Merck [Internet]. Bacterial urinary tract infections [cited 2010 Jun 6]. Available from:http://www.merck.com/mmpe/sec17/ch231/ch231b.html.
- MedlinePlus [Internet]. Urinary catheters [definition] [cited 2010 Jun 21]. Available from:http://www.nlm.nih.gov/medlineplus/ency/article/003981.htm.
- WebMd [Internet]. Cystoscopy [cited 2010 Jun 10]. Available from: http://webmd.com/hw-popup/cystoscopy.
- WebMd [Internet]. Cystometry [cited 2010 Jun 10]. Available from: http://www.webmd.com/a-to-z-guides/cystometry.