APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -The detrusor smooth muscle is the main muscle component of the urinary bladder wall. Its ability to contract over a large length interval and to relax determines the bladder function during filling and micturition.

Detailed explanation-2: -The primary function of the detrusor muscle is to contract during urination to push the urine out of the bladder and into the urethra. The detrusor muscle will relax to allow the storage of urine in the urinary bladder.

Detailed explanation-3: -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-4: -The bladder neck sphincter is under involuntary (autonomic) control while the urethral sphincter has both voluntary and involuntary components. The levator ani muscles act as a supporting hammock for this system and also have reflex as well as voluntary activity.