Female Urinary Tract
Ureteropelvic junction (UPJ) obstruction is when part of the kidney is blocked. Most often it is blocked at the renal pelvis. This is where the kidney attaches to one of the ureters (the tubes that carry urine to the bladder). The blockage slows or stops the flow of urine out of the kidney. Urine can then build up and damage the kidney. Sometimes surgery is needed to improve the flow of urine, other times the problem will improve on its own.
What Happens under Normal Conditions?
Male Urinary Tract
Kidneys make urine by filtering the blood, and removing waste, salts and water. The urine drains from the kidney into the renal pelvis and then into the ureter. Each kidney must have at least one working ureter (some have two) to carry the urine from the kidney to the bladder.