The function of the kidneys

The kidneys are two organs which are located in the back of the body behind the lower ribs. They are about 11 centimetres (four inches) long and shaped like a bean.

Function

The kidneys act as the body’s filtering system and are made up of about a million filtering units called nephrons. When blood passes through the kidneys, waste products and surplus fluid are removed and passed out of the body as urine. If the nephrons are damaged, the kidneys lose their ability to carry out this task effectively and waste products can build up.

The kidneys play other important regulatory roles, such as producing hormones to control blood pressure and maintaining healthy blood cells and bones. Kidney problems affect a large number of people in the UK, with estimates ranging from between one and four people in every 1,000.