ANATOMY

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: -The detrusor muscle is located within the walls of the bladder and is composed of smooth muscle fibers that are longitudinal and circular. The layers of the detrusor muscle start longitudinally in the inner layer, become circular in the middle layer, and then longitudinal again in the outer layer.

Detailed explanation-3: -The pudendal nerve originates from the nucleus of Onuf and regulates the voluntary actions of the external urinary sphincter and the pelvic diaphragm.