How do the kidneys work? (7 facts)

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How do the kidneys work? (7 facts)

Illustration shows the nephron, a tube-like structure that begins in the kidney cortex. Here, arterioles converge in a bulb-like structure called the glomerulus, which is partly surrounded by a Bowman’s capsule. Afferent arterioles enter the glomerulus, and efferent arterioles leave. The glomerulus empties into the proximal convoluted tubule. A long loop, called the loop of Henle, extends from the proximal convoluted tubule to the inner medulla of the kidney, and then back out to the cortex. There, the loop of Henle joins a distal convoluted tubule. The distal convoluted tubule joins a collecting duct, which travels from the medulla back into the cortex, toward the center of the kidney. Eventually, the contents of the renal pyramid empty into the renal pelvis, and then the ureter.

  1. Role. The kidney’s main role is to filter the blood
  2. Main function. This is because its main function is to remove waste products and extra water from the body
  3. Not one large filter
  4. Nephrons. Each kidney is made up of about a million tiny filtering units called nephrons (see above)
  5. Glomerulus/tubule. The nephron includes a filter, called the glomerulus, and a tubule. Each nephron filters a small amount of blood. The tubule is the drain out of the glomerulus, i.e. how the filtered blood gets out. The glomeruli are mainly in the cortex (outer area of the kidney) and tubules in the medulla (inner area)
    • The glomerulus – is like a scrunched up tiny ball of blood vessels (called capillaries)
    • The tubule – is a long U-shaped tube with three parts: proximal (means nearer to glomerulus) convoluted tubule (‘PCT’), Loop of Henle (‘loop’), and distal (further from glomerulus) convoluted tubule (‘DCT’)
  6. Two-step process. Nephrons work in two stages:
    • Filtration – the glomerulus lets waste products and water pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing
    • Reabsorption – the filtered fluid then passes through the tubule, where necessary minerals are absorbed back into the bloodstream
  7. Urine – is the final product which is passed into the bladder, and is removed from the body when you wee.

Other resources

The kidney has 6 other functions, as well as its main function (described above). They are described on CKDEx here:

This is a good video that explains how the kidneys work.

https://www.youtube.com/watch?v=hfKDA5kbL5o

Last Reviewed on 19 June 2024

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