What Is the Urinary Tract?
The urinary tract is the body’s drainage system for removing urine, which is made up of wastes and extra fluid. For normal urination to occur, all body parts in the urinary tract need to work together, and in the correct order.
The urinary tract includes two kidneys, two ureters, a bladder, and a urethra.
Kidneys. Two bean-shaped organs, each about the size of a fist. They are located just below your rib cage, one on each side of your spine. Every day, your kidneys filter about 120 to 150 quarts of blood to remove wastes and balance fluids. This process produces about 1 to 2 quarts of urine per day.
Ureters. Thin tubes of muscle that connect your kidneys to your bladder and carry urine to the bladder.
Bladder. A hollow, muscular, balloon-shaped organ that expands as it fills with urine. The bladder sits in your pelvis between your hip bones. A normal bladder acts like a reservoir. It can hold 1.5 to 2 cups of urine. Although you do not control how your kidneys function, you can control when to empty your bladder. Bladder emptying is known as urination.
Urethra. A tube located at the bottom of the bladder that allows urine to exit the body during urination.
The urinary tract includes two sets of muscles that work together as a sphincter, closing off the urethra to keep urine in the bladder between your trips to the bathroom.
- The internal sphincter muscles of the bladder neck and urethra stay closed until your brain sends signals to urinate.
- The external sphincter muscles surround the internal sphincter and provide extra pressure to keep the urethra closed. You can consciously squeeze the external sphincter and the pelvic floor muscles to keep urine from leaking out.
Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)