Question

In micturition,

• A. Urethra contract
• B. Uterus contract
• C. Urethra relaxes
• D. Ureters relax

Answer 1

The correct option is C Urethra relaxes

Micturition is flow of urine from the urethra. It is caused due to contraction and relaxation of detrusor muscles of the urinary bladder. It is controlled by the somatic and autonomic nervous system. During the storage phase the internal urethral sphincter remains tense and the detrusor muscle is relaxed by sympathetic stimulation. The parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter and urethra to relax which causes micturition. The urethral sphincter is under voluntary regulation of pudendal nerve which causes conscious relaxation during micturition. So the correct answer is 'Urethra relaxes'.