PATHOLOGY

Detailed explanation-1: -The internal urethral sphincter regulates involuntary control of urine flow from the bladder to the urethra, and the external urethral sphincter provides voluntary control of urine flow from the bladder to the urethra.

Detailed explanation-2: -INNERVATION OF THE URETHRAL SPHINCTER The striated sphincter is innervated by the pudendal nerve from the S2 to S4 nerve roots [28, 29]. The neurons that innervate the urethral sphincter originate in the cord, in an area termed Onuf’s nucleus [30].

Detailed explanation-3: -At about 200 ml of urine, the detrusor muscle begins to contract and the internal urethral sphincter muscle begins to relax. This sends signals through the nervous system and creates the “urge” to urinate. If this urge is ignored, continence may be threatened.