What are the kidneys?

The kidneys are 2 bean-shaped organs that are located toward your back, on either side of your spine, just underneath the rib cage. A kidney is about as big as a fist.

The kidneys do several things. They are responsible for making urine by filtering wastes and extra water out of the body. The kidneys also produce certain necessary hormones (erythropoietin, renin, and calcitriol) and help to regulate blood pressure by producing life-sustaining chemicals. During 1 day, the kidneys clean out 200 quarts of blood.

In each kidney, there are about 1 million nephrons. These small nephrons are the kidney parts that do the cleaning. A nephron has a glomerulus, which is a small blood vessel, and a tubule, which collects urine.

Diagram of Kidney, Nephrons and Glomerulus

What is kidney disease?

Kidney function, also called renal function, describes how well the kidneys work. If a person has 2 healthy kidneys, he or she is said to have 100% kidney function. If the kidneys lose even 30% to 40% of function, one might not even notice. A person can live with just 1 healthy kidney. However, when kidney function falls below 25%, serious problems develop. A person with less than 10% to 15% kidney function will need to have treatment to replace kidney function. The treatment choices are dialysis, a process to cleanse the blood and body, or a kidney transplant.

What is kidney transplantation?

Kidney transplantation involves placing a healthy kidney into the body where it can perform all of the functions that a failing kidney cannot. Kidneys for transplantation come from 2 sources: living donors and deceased (non-living) donors. Living donors are usually immediate family members or sometimes spouses. This is possible because a person can live well with one healthy kidney.

Deceased donor kidneys usually come from people who have willed their kidneys before their death by signing organ donor cards. All donors are carefully screened to make sure there is a suitable match and to prevent any transmissible diseases or other complications.

What causes kidney disease?

Kidney diseases occur when the nephrons are damaged and cannot filter the blood. The damage can happen quickly, such as when it is caused by injury or toxins. However, most damage occurs over a period of time. High blood pressure (hypertension) and diabetes are the 2 most common causes of the progressive type of damage to the nephrons and the resulting kidney failure (chronic kidney disease or CKD). CKD is also known as chronic renal insufficiency.

What are the symptoms of chronic kidney disease?

In the early stages, there usually are no symptoms. As the disease worsens, symptoms may include:

  • Changes in how often you need to urinate.
  • A feeling of tiredness or drowsiness.
  • Loss of appetite.
  • Swelling of hands and feet.
  • A feeling of itchiness.
  • Numbness.
  • Feeling of nausea or vomiting.
  • Muscle cramps.
  • Darkness of skin.

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