Most of us have two kidneys. They are purplish-brown and are shaped like huge beans. Kidneys are the most important waste-disposal part of the body. Through them our blood is continuously filtered to remove wastes and to help keep the chemical content of the blood in balance.
The Creator wisely gave us two of these important organs so that if one is severely damaged the other can carry on that vital filtering function. This reminds us again that “His ways [are] past finding out” (Romans 11:3333O the depth of the riches both of the wisdom and knowledge of God! how unsearchable are his judgments, and his ways past finding out! (Romans 11:33)). Life could go on even if the one remaining kidney were also partially damaged, especially if the person’s diet were carefully watched. But the normal, healthy kidneys are wonderful safeguards to our health, helping, among other things, to control our weight and blood pressure. Also, if we unwisely eat too much salt or sugar, the kidneys will get rid of the excess. However, there is a limit to this, so a wise person avoids eating too much of these.
The function of the kidneys is very complicated. Each kidney acts separately, extracting waste products from the blood. The major blood vessel that leads to the kidney is the renal artery. It comes from the liver, and the blood that travels in it contains urea. This substance is derived from proteins in our food. Digestion breaks down the proteins in food, and that which the body does not use is carried by the blood to the liver where it is changed into urea.
Now that the urea has reached the kidneys, a remarkable extraction process takes place in coiled tubes called nephrons. Each kidney has about a million nephrons which if stretched end to end in a line would be about 70 miles long.
As the blood enters the kidneys it goes into small blood vessels called capillaries where it is filtered. Part of the plasma (fluid part of the blood) enters the nephrons. The nephrons separate out the good substances (salts, sugars, amino acids, water, etc.) and return them to the blood. This process goes on continuously, and the nephrons are kept busy returning the good substances back into the blood and rejecting the waste substances. This waste part is called urine, and passes out of the nephrons into collecting tubes called ureters. Then the urine, about a quart and a half daily, passes on to the bladder and out of the body from time to time.
This complicated but amazingly efficient system contained within the body could only be designed by God. When medical science duplicates the kidneys’ blood-filtering process, it requires complicated, expensive machinery that could not fit inside the body. God alone could create and take care of the kidneys and every other part of our body as well. When we think of the wisdom that designed such an intricate body, we should exclaim like the psalmist, “I will praise Thee; for I am fearfully and wonderfully made: marvelous are Thy works; and that my soul knoweth right well” (Psalm 139:1414I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well. (Psalm 139:14)).
ML-03/16/1997