If both kidneys fail (chronic kidney disease), wastes produced by normal cell functions build up in the blood (uremia). Over time, this can threaten your health. Some people are born with one kidney or donate a kidney during their lifetime. People can function normally with just one healthy kidney. Some conditions that cause kidney damage include diabetes, high blood pressure, smoking, trauma, autoimmune diseases, hereditary conditions, and certain medications.
The kidneys also carry out many other vital functions, such as controlling blood pressure, maintaining healthy bones, and signaling the bone marrow to make adequate amounts of red blood cells.
The kidneys are part of a system that removes wastes from your body. For this system to work, the kidneys and urinary tract must do their jobs fully.
Vessels Carry Blood
Tiny blood vessels inside the kidneys carry blood to the filtering units (nephrons). These vessels also shrink or expand to control the pressure inside the kidneys.
Filters Clean Blood
Blood is cleaned as it passes through the nephrons. Each kidney has about 1 million nephrons. Wastes and excess fluid are taken out to make urine. The proper amounts of clean fluid and vital chemicals (salts and enzymes) are returned to the blood.
Urinary Tract Removes Wastes
Two tubes, called the ureters, connect the kidneys with the bladder (where urine collects). When the bladder is full, the urine is passed out of the body through a tube (urethra) during urination.