The kidneys

Most people have two kidneys. They sit at the back of the body, one on each side, just underneath the ribcage.

The kidneys filter the blood and remove waste products, which they convert into urine. Urine drains from each kidney, through a tube called a ureter, to the bladder.

The kidneys in the body
The kidneys in the body

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Blood goes to the kidney through a blood vessel called the renal artery. Renal means ‘to do with the kidney’. Thousands of tiny filters, called nephrons, filter the blood. It then goes back to the rest of the body through the renal vein.

The kidneys also help to control the balance of fluid, salt and minerals in the body. And, they maintain blood pressure.

The part of the kidney that makes urine is called the cortex.

The part that collects urine is called the medulla.

On top of each kidney there is a small gland called the adrenal gland, which produces hormones. The kidneys and adrenal glands are surrounded by a layer of fat, contained in a capsule of fibrous tissue.

Kidney structure
Kidney structure

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Back to Understanding kidney cancer

What is cancer?

There are more than 200 different kinds of cancer, each with its own name and treatment.

About kidney cancer

About 90% of kidney cancers (9 out of 10) are renal cell cancers. Renal cancer usually only affects one kidney.

Why do cancers come back?

Sometimes, tiny cancer cells are left behind after cancer treatment. These can divide to form a new tumour.