Additional Reading Introduction Urinary tract infections are a serious health problem affecting millions of people each year. Infections of the urinary tract are common only respiratory infections occur more often.
Women are especially prone to UTIs for reasons that are poorly understood.
One woman in five develops a UTI during her lifetime. The urinary system consists of the kidneys, ureters, bladder, and urethra. The key elements in the system are the kidneys, a pair of purplish-brown organs located below the ribs toward the middle of the back. The kidneys remove liquid waste from the blood in the form of urine, keep a stable balance of salts and other substances in the blood, and produce a hormone that aids the formation of red blood cells. Narrow tubes called ureters carry urine from the kidneys to the bladder, a triangle-shaped chamber in the lower abdomen.