What is urine made up of?

A human bladder usually holds around 350 millilitres (0.7 pints) of urine, though male bladders can typically hold slightly more than those of females. Urine is made up of urea, the waste by-product the body forms while breaking down protein across the body.

The kidneys will filter this out and pass it with extra water to the bladder for expulsion. Other waste products produced or consumed by the body that pass through the kidneys will also exit the body via this route.

Typically, urine is made up of 95 per cent water and 5 per cent dissolved or suspended solids including urea, plus chloride, sodium and potassium ions.