2.68a Excretion

• Urea contains nitrogen.
• Nitrogen is toxic to the body and cannot be stored.
• The original form of nitrogen are the amino acids.
• Blood circulates to the liver and the amino acids are
  broken down into the molecule known as urea.
• This then circulates to the kidneys.
• The kidneys will filter the urea from the blood.
• The urea will be added to water to form urine.
• This urine drains down the ureters.
• To then collect in the bladder.