<span>The urinary system, also known as renal system, eliminates the majority of nitrogen-containing metabolic waste products. It
</span><span> is a group of organs which filters out excess fluid and other substances from the bloodstream. The organs that compose the urinary system are: </span> kidneys, ureters, bladder, and the urethra. The result is <span>stable balance of salts and other substances in the blood.</span>
The liver primarily uses fatty acid oxidation for energy. Muscle cells use fatty acids, glucose, and amino acids as energy sources. Most cells use glucose for ATP synthesis, but there are other fuel molecules equally important for maintaining the body's equilibrium or homeostasis.