URINARY SYSTEM

651

URINARY SYSTEM

All the absorbed food-matter that passes from the intestines into the portal vein, is rich in protein and carbohydrates. The protein even is converted into amino-acid by digestion, absorbed by intestinal villi; and the amino-acids pass into the liver. In the liver, the amino-acids are broken up into urea and thrown into the blood. Also, all protoplasm and all muscles give off ammonia, which is synthesized into the urea in the liver. It is this urea which is picked up from the circulating blood that gives to urine its name. Urine however is not a solution of urea only. Urine contains a lot of water in which are dissolved urea, uric-acid, sodium chloride, sulphates, phosphates, urobilin (the pigment) which gives to urine its normal straw colour.

Kidneys, thus, do not manufacture any ingredient of the urine; they simply intelligently pick up from the blood presented to them, such of the waste products as are harmful to the system. To ensure such activity, the kidneys are richly supplied with the blood-vessels and an enormous length of tubules. A review of the work done by the kidneys fills us with wonder and amazement.

The amount of urine excreted in health per diem varies with age, sex, temperature and humidity of weather, kind and quantity of food and drink, amount of clothing, exercise and so on. But on an average, we pass 50 ounces of urine daily, whose specific gravity range from 1010 to 1020, whose reaction is slightly acid. An examination of the urine, therefore, affords us a lot of information about our diet (especially proteide-diet) and how we have been able to dispose it off.

Comments are closed.