How does the human urinary system carry urine out of the body?

The human urinary system transports urine from the kidneys to the exterior of the body through a coordinated process involving several structures:

• Production and Transport: Urine is produced in the kidneys and travels down two thin, muscular tubes called ureters. This movement is facilitated by peristaltic waves of contraction and gravity, which push urine into the bladder in discontinuous spurts.12
• Storage: The bladder acts as a reservoir, holding urine until it is ready to be voided. As it fills, the bladder wall adapts to the pressure, though eventually, sensory impulses signal the need to urinate.34
• Voiding (Micturition): When the decision to urinate is made, the detrusor muscle of the bladder contracts, and the urethral sphincter relaxes. This allows urine to flow into the urethra, the duct that conducts urine out of the body.356

This process is regulated by a combination of involuntary reflexes and conscious control from the brain, which coordinates the contraction of the bladder and the relaxation of the sphincters to ensure complete evacuation.36