Anatomy: Animals Inside

Excretory System

How do vertebrates dispose of their wastes?

Unlike many other organisms discussed above, vertebrate animals have kidneys to dispose of their metabolic wastes. For example, in humans the kidneys are two bean-shaped organs, both about the size of a fist, which are located in the middle of the back on either side of the spine. Around 20 percent of the blood pumped by the heart goes through the organs, and every day, the average human processes about 200 quarts of blood through the kidneys with about 2 quarts of urine (as waste and extra water) traveling down the ureters to the bladder, where it is stored until you go to the bathroom. Overall, the kidneys have many tasks, from keeping the concentrations of substances in your body in balance and removing wastes from the body (like urea and toxic substances) to helping to maintain your calcium levels and regulate blood pressure.


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