Urethrasphinkter

Urethrasphinkter, also known as the external urethral sphincter, is a muscular structure located around the urethra. It plays a crucial role in the voluntary control of urination by regulating the release of urine from the bladder.

Anatomically, the urethrasphinkter is composed of striated skeletal muscle fibers, allowing precise control over its contraction and relaxation. In males, it encircles the membranous part of the urethra, situated just below the prostate gland, while in females, it surrounds the portion of the urethra within the pelvic floor. The sphincter is innervated primarily by the pudendal nerve, which provides somatic motor fibers responsible for voluntary control.

Functionally, the urethrasphinkter acts in conjunction with the internal urethral sphincter, a smooth muscle that provides involuntary control. The external sphincter's voluntary contractions enable individuals to delay urination until it is appropriate to urinate, contributing to continence. During urination, the external sphincter relaxes, allowing urine to flow through the urethra.

Dysfunction of the urethrasphinkter can result in various urinary conditions, such as incontinence or retention. Urethrasphincter training and certain surgical procedures aim to restore or improve sphincter function in affected individuals.

Overall, the urethrasphinkter is a key structure in the urinary system, facilitating voluntary control over micturition and maintaining urinary continence throughout daily activities.