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πŸ«€ My body and food πŸ«€ Body organs

The kidney

The kidney removes waste from the blood, making urine. Urine flows through the ureter to the bladder and leaves the body through the urethra. On the left is a lengthwise section of a kidney.
The kidney removes waste from the blood, making urine. Urine flows through the ureter to the bladder and leaves the body through the urethra. On the left is a lengthwise section of a kidney.

πŸ“– In short

The kidneys are two small bean-shaped organs in your lower back, one on each side. Their job is very important: they clean waste and extra water out of the blood and turn it into urine, which leaves the body.

🀩 Did you know?

  • The kidneys filter about 190 liters of blood every day.
  • Together the two kidneys have about two million filtering units.
  • A kidney is about the size of your fist.
  • The kidneys also help control blood pressure.

πŸ”Ž Find out more

🌟 An amazing filter

Blood passes through the kidneys many times a day, and each kidney has about a million tiny filtering units that take out waste and return useful things to the blood.

πŸ” Urine's journey

Urine leaves the kidneys through two thin tubes and collects in the bladder, a bag that stretches like a balloon, then leaves the body when you go to the toilet.

πŸ’‘ Water helps them

Drinking enough water helps the kidneys work well. Pale urine usually shows you're drinking enough water.

🎯 One kidney is enough

A person can live with one healthy kidney, so some people donate a kidney to a sick relative.

πŸ“Έ More pictures

Blood enters the kidney through the renal artery. In the cortex and medulla, the renal artery divides into smaller tubes, each ending in a filtering unit called a nephron. In each nephron most of the blood's liquid is filtered by the glomerulus into the convoluted tubule. Cells in the tubule walls take back the substances the body needs, leaving the waste that makes urine.
Blood enters the kidney through the renal artery. In the cortex and medulla, the renal artery divides into smaller tubes, each ending in a filtering unit called a nephron. In each nephron most of the blood's liquid is filtered by the glomerulus into the convoluted tubule. Cells in the tubule walls take back the substances the body needs, leaving the waste that makes urine.

🧩 Test yourself

1 What do the kidneys do?

2 What helps the kidneys work well?

3 The kidneys filter about ?? liters of blood every day.

4 Which picture shows β€œThe kidney”?

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