Facts about Kidneys Practical Nurses Should Know

Learn about this important organ in honor of National Kidney Month

3D Illustration of the kidneys.March is National Kidney Month, and practical nurses—or anyone in a practical nursing training program—should use this month as an opportunity to learn more about this vital organ.

Why? A third of adults in the United States are at high risk for developing kidney disease, which means practical nurses are likely to see many patients who have significant risk factors. In fact, more than ten percent of American adults have kidney disease and are not aware of it. So educate yourself so you can look for the signs.

Here is some basic information about the kidneys themselves.

Size and shape:

  • An adult’s kidney is about the size of a fist.
  • In adults, the kidneys make up less than one percent of your body weight.
  • Half of one kidney is able to handle the work that two kidneys do together.
  • In someone born with only one kidney, it will grow until it is the same as what two kidneys would weigh.
  • People who only have one kidney can function, even if that kidney is only 75 percent of its original size.
  • Because it sits under your liver, your right kidney tends to be smaller than your left one, and it’s positioned lower in your body.


  • A kidney is made up of 1–2 million tiny filters, called, nephrons, that strain the blood and remove waste products.
  • After 40 years of age, each kidney starts losing its functional nephrons—1 percent of them every year—but the other nephrons tend to get larger to compensate (in a process called hypertrophy).
  • If you took all of the nephrons of two kidneys and lined them up, they would reach nearly 10 miles.

Kidneys and your blood:

  • More blood flow goes to your kidneys—120 pints per hour—than to your heart, liver, and brain. That’s 25 percent of all the blood your heart pumps.
  • The kidneys filter all of your body’s blood approximately 50 times each day—every half hour.
  • The kidneys alert the rest of the body if the blood pressure is dropping, which leads to the blood vessels constricting so the blood can continue to reach all parts of the body.
  • A drop in oxygen to the kidneys triggers the release of a hormone that increases red blood cell production.

Kidneys and urine:

  • There are about 200 quarts of fluid that the kidneys filter every day, and the body excretes about 1 percent of that amount as urine.
  • Each day, the kidneys produce between 1 and 2 quarts of urine.
  • If you become dehydrated, your kidneys will pause the production of urine until you rehydrate yourself and there is an increase in blood volume again.

Kidney stones:

  • Kidney stones are minerals and acid salts that crystallize, stick together, and collect in the kidneys.
  • They are usually formed by concentrated urine, or not drinking enough liquids. Water is especially important.
  • Other causes of kidney stones are drinking too much milk (extra calcium in the urine) and taking high doses of antacids.
  • Kidney stones hurt, but they usually don’t cause any damage.
  • The largest-ever kidney stone was as big as a coconut and weighed 2.5 pounds.

Kidney disease:

  • Once you have kidney disease, you will have it for the rest of your life. It can be slowed down, but not reversed.
  • In people with diabetes and prediabetes, the earliest sign of kidney disease is traces of protein in the urine.
  • Many people who are anemic (iron-deficient) also suffer from kidney disease.
  • People with kidney disease tend to gain weight and have swollen ankles because their kidneys are not filtering their blood properly. They retain more water and salt than they would normally.


  • Dr. Joseph E. Murray performed the first successful kidney transplant in 1954 in Massachusetts, taking a kidney from one twin and transplanting it into another. A Russian surgeon had first attempted the procedure 21 years earlier.
  • The average time someone waits on a donor list (for a kidney donation from someone who has died) is 3 to 5 years.
  • Family members make the best matches for donating a live kidney, but other people can be compatible as well.

Global health:

  • Across the globe, 1 in 10 adults are believed to have problems with their kidneys. This chronic kidney disease leads to cardiovascular disease, which is the cause of millions of premature deaths.
  • Of the world’s population, almost 2 million people now undergo either kidney dialysis or receive a kidney transplant. This is only 10 percent of the people who require the life-saving treatment.
  • A global study ranked kidney disease as no. 27 in the list of causes of death worldwide in 1990. By 2010, it had risen to no. 18.
  • 80 percent the people treated for kidney failure live in the United States, Germany, Italy, Brazil, and Japan.

Simple Guidelines

Now that you know some basic facts about kidneys, share information with your patients about how to stay healthy—including these 5 simple guidelines. Lifestyle changes that can reduce the risk of kidney disease include:

  • regular exercise and keeping off excess weight
  • avoiding over-use of pain medications such as NSAIDs (nonsteroidal anti-inflammatory drugs), which can harm the kidneys
  • maintaining a healthy blood pressure and blood sugar levels
  • quitting smoking.

Use this month to expand your knowledge of this amazing organ. Your patients will be healthier for it!

This post is part of the weekly blog of the Salter School of Nursing and Allied Health, located in Manchester, NH. We care about supporting all our students pursue their career goals. Visit us online to learn more, or reach out to schedule a campus tour by calling (603)-622-8400.