2.68a Excretion

understand how the kidney carries out it's roles of excretion and osmoregulation.

kidney is responsible for excretion of urea.
urea contains nitrogen which is toxic to our body in excess amounts.
most common form of nitrogen base molecules in our bloodstream are the amino acids.
blood circulates to the liver and amino acids broken down into urea.
kidney filters urea and adds water to form urine
urine passes down to the bladder to be removed from body