About Us | Privacy | Site Map
Font Size
A
A
A


Kidney Stones

Kidney Stones Overview

The kidney acts as a filter for blood, making urine and removing waste products from the body. It also helps regulate electrolyte levels that are important for body function. Urine drains from the kidney into the bladder through a narrow tube called the ureter. When the bladder fills and there is an urge to urinate, the bladder empties through the urethra, a much wider tube than the ureter.

In some people, chemicals crystallize in the urine and form the beginning, or nidus, of a kidney stone. These stones are very tiny when they form, smaller than a grain of sand, but gradually can grow over time to a 1/10 of an inch or larger. Urolithiasis is the term that refers to the presence of stones in the urinary tract, while nephrolithiasis refers to kidney stones. The size of the stone doesn't matter as much as where it is located.

When the stone sits in the kidney, it rarely causes problems, but when it falls into the ureter, it acts like a dam. As the kidney continues to function and make urine, pressure builds up behind the stone and causes the kidney to swell. This pressure is what causes the pain of a kidney stone, but it also helps push the stone along the course of the ureter. When the stone enters the bladder, the obstruction in the ureter is relieved and the symptoms of a kidney stone are resolved.



Next: Kidney Stones Causes »

Viewer Comments & Reviews

Kidney Stones - Symptoms Experienced

The eMedicineHealth physician editors ask:

For kidney stones, what were the symptoms and signs you experienced?

Comment submissions for this question have ended. Viewer Comments FAQs
See 27 Viewer Comments & Reviews

View Comments


Printer-Friendly Format  |  Email to a Friend

Women's Health

Find out what women really need.

Are You Depressed? Take the Quiz


Kidney Stones

Blood in the Urine Overview

Blood in the urine is a common problem. The medical term for red blood cells in the urine is hematuria. Sometimes blood in the urine is a sign of a serious problem in the urinary tract, while other times it is not serious and requires no treatment. Only after a thorough evaluation by a health-care provider should blood in the urine be attributed to a non-serious cause.

The urinary tract consists of the following structures:

  • Kidneys: You have two kidneys, located closer to your back than your front at about waist level. The kidneys filter the blood in your body and produce urine.


  • Ureters: These narrow, hollow tubes carry urine from the kidneys to the bladder.


  • Bladder: The bladder is a balloon-like organ that holds urine until it is convenient for you to empty your bladder (urinate).


  • Urethra: This narrow, hollow t...

Read the Blood in the Urine article »



Read What Your Physician is Reading on eMedicine

Nephrolithiasis »

Nephrolithiasis is a common disease that is estimated to produce medical costs of $2.1 billion per year in the United States.

Read More on eMedicine »

Medical Dictionary