New Blog 1: Living With One Kidney

Living With One Kidney

This is an excellent question, especially because kidney disease and kidney transplants are so common (approximately 10,000 to 15,000 Americans receive kidney transplants each year). Most humans are born with two kidneys as the functional components of what is called the renal system, which also includes two ureters, a bladder and a urethra. The kidneys have many functions, including regulating blood pressure, producing red blood cells, activating vitamin D and producing some glucose. Most evidently, however, the kidneys filter body fluids via the bloodstream to regulate and optimize their amount, composition, pH and osmotic pressure. Excess water, electrolytes, nitrogen and other wastes get excreted as urine. These functions maintain and optimize the "milieu interieur" (internal environment) of the body--the fluids in which our cells live.Life is incompatible with a lack of kidney function (though hemodialysis can act as a substitute). But unlike the case with most other organs, we are born with an overabundant--or overengineered--kidney capacity. Indeed, a single kidney with only 75 percent of its functional capacity can sustain life very well.This overengineering supplies us with 1.2 million of the basic functional filtering element, the microscopic nephron, in each kidney. Nephrons are tiny tubes that filter the blood plasma, adjust and then return optimized fluid to the body. Under most conditions, though totaling only a few pounds, the kidneys receive about 20 percent of all the blood pumped from the heart. Each day, about 120 liters of fluid and particles enter into the nephron to be filtered.