Within the male reproductive system, the epididymis and the vas deferens make up the duct system of the male reproductive organs. These ducts lie alongside the testicles. The epididymis is a set of two coiled tubes (one for each testicle) that connects to the vas deferens.
The epididymis has three parts. Near the top of the testicles is the head of the epididymis, which stores sperm until it is ready to undergo maturation. Next is the body, a long, twisted tube where the sperm matures. This maturation takes approximately one week. Last is the tail, which connects to the deferent duct, also referred to as the ductus deferens or vas deferens. From here, the sperm is transported to the ejaculatory duct.
The epididymis is a little known and well-researched part of the male reproductive system. Researchers in the United Kingdom noticed that one of the side effects of a drug used to treat conditions like schizophrenia and high blood pressure is to block ejaculation. These researchers uncovered the mechanism of action of this medication: By closing the tubes in the epididymis and vas deferens, the passage of semen is prevented. The semen then remains in the vas deferens tubes and is naturally recycled by the body.
These researchers developed a male birth control contraceptive product called the clean sheets pill. Learn more about it and other safe reversible non-hormonal male contraceptive methods here.