Which of the following statements best describes how normal voluntary urination occurs?

A) The detrusor muscle relaxes to pass urine through the urethra.
B) The external urethral sphincter contracts to force urine out of the bladder.
C) Stretch receptors send sensory impulse to the voiding reflex center.
D) Voluntary control of the internal urethral sphincter leads to bladder emptying.

Question

Anahit Sargsyan · Accepted Answer

Final Answer : B , Explanation :  Micturition (passing urine)occurs when the contracted detrusor muscle pushes stored urine through the relaxed internal urethral sphincter into the urethra.The detrusor muscle must contract,not relax,to pass urine through the urethra.Stretch receptors do send sensory impulses to the voiding reflex center; however,this only is a precursor to voiding.Voiding does not occur at that time.The internal urethral sphincter is not under voluntary control.

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