Urethra

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The urethra (pl.: urethras or urethrae) is the tube that transports urine from the bladder to the urethral meatus of the penis or vulva in placental mammals. In males, it also transports semen through the penis during ejaculation. The external urethral sphincter is a striated muscle that allows voluntary control over urination. The internal urethral sphincter, formed by the involuntary smooth muscles lining the bladder neck and urethra, is innervated by the sympathetic division of the autonomic nervous system in males and females.

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