Final answer:
The root word that means vessel or vas deferens is 'vas'. The vas deferens is a key component of the male reproductive system, responsible for transporting sperm from the epididymis to the ejaculatory duct.
Step-by-step explanation:
The root word that refers to the vessel or vas deferens is vas. The vas deferens, also known as sperm ducts, are a pair of thin tubes that function in the transport of sperm from the epididymis to the ejaculatory duct. These structures are essential for male fertility and are an integral part of the male reproductive system. The vas deferens is composed of ciliated epithelium and smooth muscle, which aid in the movement of sperm. During ejaculation, sperm travel from the epididymis through the vas deferens and into the ejaculatory duct with the aid of the smooth muscle contractions. This duct system is eventually connected to the urethra, through which sperm leave the body. The procedure to cut and seal the vas deferens for birth control is known as a vasectomy.