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Page 6
| The Kidneys |
| The kidneys take arterial blood from the renal arteries and squeeze it through half-a-million little filter tubes (the nephrons) which separate the blood into thick protein sludge and watery serum. The serum passes lymph-like through the tubes, allowing all the important constituents to be absorbed back into the sludge until the exiting blood is restored and cleaned. A minute amount of fluid (containing waste solutes and acids) is passed out into the kidney pelvis and ureters as urine. The result is that sodium or potassium is retained (under the influence of the adrenal cortex), water is retained or not (the pituitary) and the acid/alkaline balance is maintained. The overall control of acid and alkaline is the joint effort of the kidneys and lungs. |
| Further, the compensatory reactivity and constriction of blood vessels and the heart is potentiated by kidney proteins, which are acted on by the liver and activated in the tissues. The kidneys produce renin, which is manipulated further by the liver and liver-synthesized protein and becomes vasoconstricting, when needed, in blood vessels. This allows blood to flow to the brain when we stand, to back off when we sit, etc. Basically, the kidneys' primary function is to control blood volume, quality and dispersal, with urine production simply a means to this end. The kidneys are organs that hold in far more than they let out. |
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