A UTI is when bacteria gets into your urine and travels up to your bladder. UTIs cause more than 8.1 million visits to health care providers each year. About 10 in 25 women and 3 in 25 men will have symptoms of at least 1 UTI during their lifetime.

How Does the Urinary Tract Work?

The urinary tract makes and stores urine, one of the waste products of your body. Urine is made in the kidneys and travels down the ureters to the bladder. The bladder stores the urine until it is emptied through the urethra, a tube that connects the bladder to the skin, when you urinate. The opening of the urethra is at the end of the penis in a male and in front of the vagina in a female.

The kidneys are a pair of fist-sized organs in the back that filter liquid waste from the blood and remove it from the body in the form of urine. Kidneys balance the levels of many chemicals in the body (sodium, potassium, calcium, phosphorous and others) and check the blood's acidity. Certain hormones are also made in the kidneys. These hormones help control blood pressure, boost red blood cell production and help make strong bones. 

Normal urine has no bacteria in it, and the one-way flow helps prevent infections. Still, bacteria may get into the urine from the urethra and travel up into the bladder.