Excretion is an essential process in which waste products are removed from the body. Without excretion, waste products build up in the body and cause serious health issues.
Urea is a mixture of nitrogenous wastes that damage the body if not removed by the excretory system. Blood is important to the excretory system. It carries waste from cells through the bloodstream to the excretory organs for removal from the body.
The excretory system consists of many parts and organs that work as a whole. It rids the body of metabolic waste, which contains salts, carbon dioxide and urea. The lungs remove carbon dioxide, absorbing and removing waste while providing oxygen to the body. The skin is part of the excretory system and helps rid the body of contaminants through perspiration. Perspiration removes urea from the body in a water-based liquid excreted from sweat glands located in the skin.
The urinary system is comprised of the kidneys, the urethra, the ureters and the bladder. The kidneys filter contaminants from the bloodstream and remove them from the body as urine. The kidneys also serve to diffuse any useful substances that pass through the urinary system, sending them back into the bloodstream to be utilized.