ANATOMY

Detailed explanation-1: -The urethral sphincter can be used to control micturition. Voiding urine begins with voluntary relaxation of the external sphincter muscle of the bladder. Parasympathetic impulses induce contractions of the bladder and relaxation of the internal sphincter [18].

Detailed explanation-2: -The internal urethral sphincter relaxes, allowing for urine to pass out of the bladder into the urethra.

Detailed explanation-3: -This results in contraction of the detrusor muscle of the bladder and relaxation of the smooth muscle of the internal urethral sphincter.

Detailed explanation-4: -When one relaxes the voluntary muscle, the involuntary muscle relaxes as well. When these muscles are relaxed, they open up allowing for urine to flow out of the bladder through the urethra and out the body. When these muscles are contracted, they keep urine in the bladder.

Detailed explanation-5: -Activation of beta-adrenoceptors causes relaxation of the urinary bladder and contraction of the external urethral sphincter, which consists of fast-contracting skeletal muscles.