What are kidneys and what do they do?

The kidneys are bean-shaped organs, each about the size of a closed fist. They are located near the middle of the back on either side of the spine.

The kidneys are extremely sophisticated organs. Every day, a person’s kidneys keep processing his or her blood to filter out waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores the urine until it is released.

In fact, kidneys process about 1.5 liters of blood per minute – that is about 2,200 liters of blood per day which means that the entire blood in the body gets cleaned about 440 times in a day!


Where do the wastes come from?

We understand that the excess water that the kidneys filter out come from what we drink. What about the wastes? What are these wastes and where do they come from? These wastes come from two ways – one, from the normal breakdown of active tissues such as the muscles and two, the food we eat. When the muscles of our body work – to walk, to lift things and numerous other activities which we don’t even realize, they produce these wastes.

After the body has taken what it needs from the food we eat, the rest of it is also treated as waste. If these wastes are not removed by the kidneys, they start building up in the body and start damaging the body. The kidneys also do some other very important things:

  • Production of Erythropoietin: Erythropoietin is a hormone that stimulates production of red blood cells (RBCs) in the bone marrow. Whenever the RBC count goes down in the blood, the quantity of oxygen available in the blood goes down. So, the tissues in the body start demanding more oxygen. This causes the kidney to release more erythropoietin into the blood. This erythropoietin stimulates the bone marrow to produce more RBCs. This in turn increases the oxygen carrying capacity of the blood.
  • Production of Calcitriol: Calcitriol is the active form of Vitamin D3 that is extremely important for the absorption of Calcium from the intestines into the blood. This causes the bones to remain in good condition as the required Calcium is obtained.
  • Production of Renin: Renin controls the blood pressure in the body.

Consequently when the kidneys are not functioning as well as they should, there are three other important side effects apart from the build-up of toxins and water in the blood. These are:

  • Anemia: Reduction in RBCs in the body. This reduces the oxygen carrying capacity of the blood.
  • Deficiency of Vitamin D3: Because of this, the absorption of Calcium from the intestines into the blood and consequently, the conditions of the bones is affected.
  • High Blood Pressures: The blood pressure goes out of control. This uncontrolled high blood pressure puts a strain on the heart as well leading to problems such as Left Ventricular Dysfunction.