The urinary system or renal system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder and the urethra. The female and male urinary system are very similar, differing only in the length of the urethra.
Urine is formed in the kidneys through a filtration of blood. The urine is then passed through the ureters to the bladder, where it is stored. During urination (peeing) the urine is passed from the bladder through the urethra to the outside of the body.
About 1-2 litres of urine are produced every day in a healthy human. Although this amount may vary according to circumstances such as fluid intake.
- The excretory system removes metabolic and liquid toxic wastes as well as excess water from the organism, in the form of urine.
- The excretory system is a passive biological system that removes excess and unnecessary materials from an organism, so as to help maintain homeostasis within the organism and prevent damage to the body.
- It is responsible for the elimination of the waste products of metabolism as well as other liquid and gaseous wastes. As most healthy functioning organs produce metabolic and other wastes, the entire organism depends on the function of the system; however, only the organs specifically for the excretion process are considered a part of the excretory system
As your body performs the many functions that it needs in order to keep itself alive, it produces wastes. These wastes are chemicals that are toxic and that if left alone would seriously hurt or even kill you.
For example, as your cells break down amino acids, they produce a dangerous toxin known as ammonia. Your liver converts the ammonia to another substance, called urea. The urea is turned into urine in the kidneys and is then carried in the ureters to the bladder.