To better understand pyelonephritis, it helps to understand the anatomy of the kidneys and genitourinary tract.
The kidneys are located in the back of the abdomen, below the ribcage and on either side of the spine. Each kidney weighs about 1/4 pound (0.6 kg) and is about the size of a fist.
The kidneys filter waste from the bloodstream and produce urine. The kidneys also regulate the salt and water balance for the body.
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