Ayurvedic point of view-Physiology of Urinary System

Urinary System
The abode of urine called ‘Mūtrāśaya’ supports the wastes ofthe body and is one of the very important vital structures in the body. Minute‘Nād īs’ (specialized structures meant fortransportation) arising from the large intestine, carry the urine continuouslyand contribute in the urine formation. This process is just similar to themanner in which many small tributaries and rivers contribute their water to theocean. Openings of these ‘Nād īs’ cannot be tracedout because of their minuteness and huge number. Because of this urine, carriedby these ‘Nād īs’ from the proximity of stomach,‘Basti’ (urinary bladder) gets filled up continuously throughout the dayand night through the process of filtration. This process is similar to thefashion in which a new earthen pot kept immersed in the water up to its neck getsfilled up (by the water) after some time through its sides (Su. Ni. 3/20-24).‘Mūtrāśaya’ in the above reference has been told to be very vital, andtherefore, definitely is indicative of kidneys, from a functional point ofview. Suśruta probably knew the role of kidneys in the formation of urine. Heprobably also had observed that there exists some relationship between waterintake and urine formation. The fact that increased water intake results in increasedurinary output must have been the reason for this observation. Also, decreasein the urinary output observed in the persons suffering from diarrhea orvomiting might have been another reason. So, he proposed the existence ofinvisible minute channels connecting GIT and urinary tract. This prediction isnot totally wrong because cardiovascular system definitely connects both thesesystems. Water is absorbed from the gut into the venous circulation and this iscarried to the kidneys through the arterial system. Also, the capillaries atGut and glomerulus are definitely microscopic. The example of mud pot in theabove explanation indicates the role of filtration played by the kidneys in theformation of urine. Thousands of ‘Nād īs’ taking part inthe process of filtration may stand for nephrons from a functional point of view.