| Urinary stones have affected mankind since time immemorial. It would be fascinating to know that the first evidence of urinary stones dates back to 4800 B.C., when a bladder stone was discovered in an Egyptian mummy at E1 Amrah ? Egypt. Information about urinary stone disease can also be found in ancient Sanskrit literature in India.
Excretion can be defined as the removal of toxic waste products of metabolism from the body. These wastes can be either solid, liquid or in the gaseous state. The liquid wastes are ammonia and urea, which exist in the blood along with the nutrients and other useful substances. So there is a need of complex organ that may separate or filter out the dissolved excretory wastes from blood while retaining the nutrients in the latter. Two kidneys in human beings are such organs that perform this task. There is a distinct advantage of the two kidneys in our body. If one kidney fails, the other can still deal with functions of excretion and regulation. |