What is the function of sphincter in urinary system?

Sphincters are essential components of the urinary system as they play a crucial role in controlling the flow of urine. There are two sphincters associated with the urinary system:

1. Urethral Sphincter: The urethral sphincter, also known as the external urethral sphincter, surrounds the urethra, which is the tube that carries urine from the bladder to the outside of the body. The urethral sphincter acts as a valve that controls the voluntary release of urine. It remains contracted to prevent urine leakage and relaxes when urination is desired.

2. Internal Urinary Sphincter: The internal urinary sphincter is a smooth muscle sphincter located at the junction of the bladder and urethra. It is an involuntary sphincter that remains contracted to help maintain urinary continence. It relaxes during urination to allow urine to flow out of the bladder.

These sphincters work together to ensure proper urine storage and release. When the bladder fills with urine, the pressure inside increases, leading to the relaxation of the internal urinary sphincter. At the same time, the urethral sphincter remains contracted, preventing urine leakage. When urination is desired, the brain signals the relaxation of the urethral sphincter, and the force of the bladder contractions pushes the urine out through the urethra.

Dysfunction or damage to either the internal urinary sphincter or the urethral sphincter can lead to urinary incontinence, which is the involuntary loss of urine. In such cases, medical intervention may be necessary to restore proper sphincter function and control over urination.