The urinary tract consists of two kidneys , located deep in the abdomen. The kidneys filter waste substances from the blood and excrete them as urine . Urine travels from the kidneys in small tubes called ureters to a single bladder which stores urine. Urine passes to the outside of the body through the urethra . A urinary tract infection is usually caused by bacteria entering the urethra.
Bacteria can cause infection in any portion of the urinary tract.
In women, the urethra is short and bacteria from the vagina and rectum can easily enter the urinary tract. Diarrhea, sexual activity, and wiping the rectal area before the urethral area after urinating can transfer bacteria into the urethra. In men, the urethra is long and bacteria are less likely to enter the urinary tract. Urinary tract infections in males usually imply an underlying problem. Anatomical irregularities in any part of the urinary tract can contribute to development of a urinary tract infection.