The Incredible Kidneys
Around four to five thousand litres of blood flow through the human kidneys every day. The blood contains toxic molecules taken up with food and/or metabolic degradation products that the human body wants to get rid of.
Your kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals—such as sodium, calcium, phosphorus, and potassium—in your blood. Without this balance, nerves, muscles, and other tissues in your body may not work normally.Your kidneys also make hormones that help control your blood pressure, make red blood cells, and keep your bones strong and healthy.
But the kidneys can do a lot more: they also ensure that the blood does not become too diluted and that the concentration of dissolved salts is kept at an appropriate level. The kidneys are highly selective and very sensitive. They “know” exactly how much salt needs to be withdrawn from the blood in order to maintain vital salt levels. In addition, the renal filter retains proteins (e.g., enzymes) dissolved in the blood, which are still required by the organism. Hormones must also be filtered out after they do their job and excess chemicals such as sugars must be removed. Water level must also be kept in balance. Though 95% of urine is water, the other 5% contains poisons that, if allowed to build up in our systems, would be fatal.
We are able to live with only one kidney and, in fact, some live with partial functioning of one kidney. But if the kidneys fail entirely, that person has only days to live without dialysis, that is, artificial blood filtration.
“In my lectures I often say that the kidneys are the actual brain of humans,” said Dr. Tobias Huber from the Department of Nephrology at the Freiburg University Medical Centre, adding “well, of course that’s not quite true, but it is important to highlight the key role played by the kidneys as often as possible.”
How all this works is too complicated for an article this size. Guyton’s Medical Physiology textbook contains 70 pages on body fluids and the work of the kidneys and bladder. The chemistry involved is staggering. The most complex blood filters designed by engineers cannot begin to duplicate the work of the kidney. It would be folly to try to explain the work of a dialysis machine as the result of a series of amazing accidents. Intelligent engineers have worked years to develop machines that can somewhat duplicate the work of the kidney. Why is it so difficult then to admit the kidney is designed by someone superior to these engineers?
A further thought– if man and animal evolved, it is obvious that the kidney would be required in the beginning, else the life form would die of toxemia within days. This is yet another example of the absurdity of trying to explain complex interdependent required systems of the body as the result of random changes over long periods of time.