The role of the liver is to filter toxins and eliminate them from the body in the form of nitrogenous waste. Nitrogenous wastes are ammonia, urea and uric acid. In the human body, only ammonia and urea are produced, and the liver quickly converts harmful ammonia into tolerable urea for excretion from the body. Ammonia is toxic to humans at high concentrations (see Table 1). Ammonia is the byproduct of protein breakdown. Ammonia is formed by the breakdown of amino acids extracted from excess proteins. The liver converts ammonia into urea, which is then eliminated from the body as urine (BBC Science and Nature – Human Body and Mind – Organ Layer – visited April 14, 2014). This conversion occurs through the urea cycle (see Figure 1) in the liver. The urea cycle is the conversion of carbon dioxide and ammonia into urea and water. Once ammonia is converted to urea, it is transferred into the bloodstream and the kidneys. Then the kidneys filter urea from the blood. Urea is mixed with water and urine is expelled from the body via the bladder while maintaining isotonic fluid balance. Urea is the byproduct of the urea cycle, which converts highly toxic ammonia into tolerable urea. The liver is the only place in the body where the complete urea cycle is observable (New/Infant/Child with hyperammonemia – 2013). Fluid balance is maintained throughout the body but the kidneys play a major role. The kidneys normalize the amount of water in the body and balance the absorption of mineral ions into the blood (Homeostasis – Kidneys and fluid balance – ABPI – resources for schools – visited April 14). They achieve a state of homeostasis which, according to ABPI resources for school...... middle of article...... [Online] Available at: http://www.pineapplejuice.com /the-health-benefits-of-pineapple-juice.html [Accessed: April 14, 2014].StyleCraze. 2014. Top 10 Benefits of Pineapple Juice for Skin, Hair and Health. [Online] Available at: http://www.stylecraze.com/articles/benefits-of-pineapple-juice-for-skin-hair-and-health/ [Accessed: April 14, 2014]. Urea cycle diagram. nd [online image] Available at: http://newenglandconsortium.org/wp-content/uploads/2012/06/urea-cycle-rev-6-26.jpg [Accessed April 14, 2014].Walker, R. 2014 e.explore the human body. London: Dorling Kindersley Limited. Wikipedia. 2013. Urea cycle. [Online] Available at: http://en.wikipedia.org/wiki/Urea_cycle [Accessed: April 14, 2014].YouTube. 2012. The excretory system: from your heart to the toilet - CrashCourse Biology #29. [Online] Available at: http://www.youtube.com/watch?v=WtrYotjYvtU [Accessed: April 14 2014].