WebMD offers an analysis of how urine flows from the kidneys and through the urinary system. The kidneys filter waste products and water from the blood, creating urine, which eventually travels through the urinary tract and leaves the body during urination, according to WebMD.
Urine travels down a pair of ureters attached to the kidneys and flows into the bladder, notes WebMD. The bladder stores the urine until the person gets the urge to urinate. During urination, the urine leaves the body through the urethra, which is a tube connected to the bladder. Normally, the bladder empties completely once urination begins.