Final answer:
A vasectomy is a medical sterilization procedure where a portion of the vas deferens is removed or sealed, interrupting sperm transport and causing sperm to remain in the epididymis.
Step-by-step explanation:
The medical procedure for the excision of a duct, specifically a partial excision of the vas deferens, is termed a vasectomy. This is a surgical sterilization procedure predominantly used for male birth control. During a vasectomy, a section of the vas deferens, which is a duct responsible for transporting sperm from the epididymis to the ejaculatory duct, is removed or sealed. This disrupts the path that sperm would take during ejaculation. If sperm are unable to travel through the vas deferens—due to a vasectomy or lack of ejaculation—they remain in the epididymis, which is a tightly coiled tube located on the back of each testicle where sperm mature and are stored before ejaculation. After vasectomy, sperm continue to be produced by the testes but are reabsorbed by the body since they cannot exit the reproductive system.