2.68a Excretion

• The urea contains nitrogen which is toxic to the body and cannot be stored.
• The original form of nitrogen are amino acids.
• Blood circulates into the liver and breaks down, and  it is converted into Urea.
  
• It re-enters the blood stream and circulates to both kidneys.
  
• The kidneys filter the urea from the blood and will be added to water to form urine.