The upper system is comprised of the kidneys, the renal pelvis and two ureters. The lower system is comprised of the bladder and the urethra.
What is urine?
1. Kidneys 2. Ureter
3. Urine bladder 4. Urethra
Urine is a type of waste product that comes from your kidneys. Your urine is guided via the renal pelvis to the ureters. The ureters press the urine at intervals down into the bladder. Once it reaches the bladder, your urine gathers there. When your bladder contains about 200 ml of urine, your bladder usually signals your brain with an indication that the bladder is starting to fill up. Your bladder can hold about 400-600 ml of urine, but by then most of us have gone to the toilet and emptied our bladders. Normally, people empty their bladders 5-7 times a day. The total amount of urine is usually about 2 litres.