Let us know about new materials and/or information. » Share your info

What is known about kidneys and kidney health?

What are kidneys?

Kidneys are important organs that get rid of waste from our blood and keep the water in our body balanced [1]. This waste leaves the body as urine (also known as wee).

Most people have two kidneys, which are located on the right and left side at the back of the abdomen (the middle part of the body) just below the chest and rib cage. Each kidney is about 11.5 centimetres long, 5-7.5 centimetres broad and 5 centimetres thick, and weighs about 150 grams [1, 2].

Return to top

What do kidneys do?

The kidneys do many things to keep us alive and healthy [1].

  • They carry away waste from the blood and get rid of it in urine.
  • They adjust the amount of fluid in our bodies.
  • They help control blood pressure by making a chemical called renin (which raises blood pressure) [1].
  • They send out other chemicals to help keep the body balanced.

Return to top

How do kidneys work?

The kidneys clean all blood in the body every two minutes. They do this by filtering the blood with small groups of blood vessels (known as a glomerulus – which is from the Greek word for filter - the plural is glomeruli) [1]. There are about 1 million glomeruli in each kidney. Blood is filtered in the glomerulus, and water and wastes are passed out as urine. Urine collects in the middle of each kidney (an area called the renal pelvis) [3]. The kidneys make more urine when there is too much fluid in the body, and less urine when the body needs fluids (for example when you are dehydrated) [1].

The water passing from the body as urine passes through the ureters (two thin-walled tubes of around 30 centimetres in length) into the bladder (a muscular container with a capacity of around 500 millilitres) [2]. This urine is stored in the bladder and then leaves the body through the urethra (a small passage from the bladder to the outside of the body) [3].

Return to top

Why do kidneys stop working?

Our kidneys may stop working for a number of reasons [1];

  • high blood pressure (also known as hypertension), which causes blood vessels in the kidneys to get skinny and hard so the kidneys don’t get enough blood,
  • infections, which spread through the blood and make the kidneys sick,
  • having diabetes (see diabetes section) for many years, and
  • genetics - some people are more likely to have problems with their kidneys because of something that’s inherited (other people in their family may have similar problems).

Return to top

How can we keep kidneys healthy?

Things we can do to keep our kidneys healthy [4];

  • keep our homes clean and free from germs,
  • keep our stress levels low (try to be calm, not get too excited or angry),
  • have regular exercise,
  • eat plenty of fresh, healthy food and limit the amount of fatty and take-away food we eat,
  • limit the amount of alcohol and tobacco we use, and
  • drink lots of clean water.

Return to top

What type of kidney health problems are there?

As you know, there are two main parts of the body involved in filtering blood and waste and in the passing of urine - the kidneys and the urinary tract (ureters). These parts make up what is known as the urinary system.

There are two types of problems (or disorders) of the urinary system;

  1. problems that damage the kidneys (known as renal disorders - for example; (a) renal failure or end-stage renal disease (ESRD) and (b) glomerulonephritis.
  2. problems that damage the urinary tract (for example; urinary tract infection).

Return to top

Renal Disorders

End-stage renal disease (ESRD)

Chronic renal failure is the slow loss of kidney function that gradually gets worse over several years until the kidneys stop working for good. This is also known as end-stage renal disease (ESRD) [2]. People with ESRD need dialysis (a medical procedure that does the work of the kidneys) or a transplant (a new healthy kidney put into the body). If left untreated, ESRD leads to death.

Return to top

Glomerulonephritis

Glomerulonephritis is a sickness that causes damage to the glomerulus [5, 6]. Damaged glomeruli let protein and red blood cells leak into the urine, and may stop waste from being properly filtered out of the body [1]. This can lead to fluid build-up in the body causing swelling in parts of the body (for example, face, hands, ankles and feet). Sicknesses related to glomerulonephritis include; acute post-streptococcal glomerulonephritis ( APSGN) (an inflammation of the glomeruli following an infection, such as one in the throat).

Return to top

Urinary tract problems

Urinary tract infection (UTI)

A urinary tract infection (UTI) is an infection or sickness in the upper or lower part of the urinary tract [1]. Usually, a UTI is caused by bacteria (tiny germs that can be killed with antibiotic medicine). Bacteria can enter the urethra and travel to the bladder, but they usually get flushed out with urine without causing an infection. Sometimes, however, the bacteria multiply and cause an infection. Women are more likely to get this infection than men, and older people are more likely than younger people.

Some people with a UTI do not show signs of having it. The signs for lower UTI are;

  • frequent urination,
  • painful urination, and
  • tenderness in the lower pelvic area [6].

The signs for an upper UTI infection are;

  • fever,
  • back or loin pain, and
  • chills [5, 6].

Having a UTI is not always a serious problem, but having it often, having it for a long period of time and/or having it at the same time as other sicknesses (such as diabetes) can lead to more serious kidney damage.

Return to top

References

1. National Kidney and Urologic Diseases Information Clearinghouse (2002) Your kidneys and how they work. Retrieved 4 October 2006 from http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/index.htm
2. Thomas C, ed. (1997) Taber's cyclopedic medical dictionary. Philadelphia, PA: FA Davis Company
3. (2007) Dictionary.com. Retrieved 19 April 2007 from http://dictionary.reference.com/
4. Centre for Disease Control (2002) Guidelines for the control of acute post-streptococcal glomerulonephritis. Casuarina: Department of Health and Community Services, Northern Territory Government
5. Braunwald E, Fauci, AS, Kasper, DL, Hauser, SL, Longo, DL, Jameson, JL, eds. (2001) Harrison's principles of internal medicine. 15th ed. New York: McGraw-Hill
6. Kumar PJ, Clark ML (1994) Clinical medicine: a text book for medical students and doctors. London: Bailliere Tindall

Return to top

Return to kidney health home

Let us know about new materials and/or information. » Share your info
Last updated: 2 August 2007