Turek on men's health
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Award-winning urologist - and pioneer in Men's Health - Dr. Paul Turek blogs weekly about issues such as infertility, vasectomy and vasectomy reversal, sexual and hormonal dysfunction and more. Keep up with the latest on this fascinating field of medicine.

A Day in the Life of the Epididymis

epididymal anatomy in the human
Epididymis: most of the colored section of the figure (A-C) and one of the most important tubes in your body. (Courtesy: Wikipedia.org)

The epididymis has been on my mind recently. The Epi-WHAT-amus? What is that? Well, for one, it’s probably the shortest 5-syllable word you’ve ever heard. And, it happens to be the name of an organ that can spell the difference between being a fertile or infertile guy.

Anatomy First

The epididymis is an 18-foot long, tightly coiled, almost microscopic, sperm-filled tubule that could fit into a pen cap. It sits on top of, and wraps behind, the testicle. Sperm pass from the testicle into the epididymis and, over about 12 days, get rubbed, shined and gassed up for the big day.

At the end of this trip, sperm are ready to fly, prepared to meet an egg, anywhere, anytime. However, until ejaculation occurs, some 200 million sperm are kept in check within the epididymis just waiting to be set free.

Sperm Maturation

Sounds funny, but passage of sperm through the epididymis is a lot like going through puberty. A lot of serious functionality is acquired during this time that prepares sperm for the real world. Here is a short list of what happens to sperm in the epididymis:

  • Improved structural rigidity that helps with motility or movement.
  • Acquire the ability to move purposefully.
  • Learn to “smell” (chemosense) the fluid released during female ovulation. This helps them know where to go once ejaculated.
  • Acquire the ability to fertilize eggs.

The epididymis is also a “filter” that sorts out and destroys sperm that, for some biological reason, do not pass muster. This activity is increased several hundred-fold after a vasectomy when sperm fills the epididymis with nowhere else to go because of the downstream roadblock.

So, much like the inconspicuous, nerdy guy in the back of the class, the epididymis, in its own quiet way, is critical for normal male fertility. Beware though, that it can also be a problem child. Here’s how:

Epididymis as Elephant

Here’s why I have been thinking epididymal thoughts. Based on my recently published research on how ejaculated sperm recovers following reversal of vasectomy, I am now convinced that the epididymis plays a key role. Although sperm counts are similar after reversal of younger and older (>15 years) vasectomies, sperm motility is significantly lower after reversal of older vasectomies. And lower motility means longer time to pregnancy or even frank infertility after reversal. Given what you now know about how the normal epididymis influences sperm, you may surmise that it is the elephant in the room when it comes to impaired sperm movement after vasectomy reversal.  If I can now figure out a way to help the epididymis get its mojo back after reversal, then I am pretty sure that natural fertility rates will improve as well. After all, if more sperm were given directions, maybe fewer would be needed to get the job done!

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7 Responses to “A Day in the Life of the Epididymis”

    • Paul Turek, MD

      Dear Chyke, I have many patients like you. Read, read and read. Call if you need to talk with us. But always have some hope.

  1. Peter

    Hi,am from Kenya been reading your blogs and going through your website and i know your the person i need to see.i underwent a hernia operation in 2005 and a few months later i discovered i could not produce sperm which i could produce before the surgery.i have visited several doctors here in Kenya to no avail ,just wondering if you can visit Kenya for men like me and many others who really need your expertise. I Will be happy to hear from you. Regards Kanyote.

    • Paul Turek, MD

      Dear Peter/Kanyote: I would love to visit Kenya, but I am not licensed to practice medicine there. I have spent a good deal of time in Senegal but way back when I was training in medicine. Consider a Second Opinion consult as you may have obstructive azoospermia due to mesh hernia repair.

  2. Derick L Corea

    Paul Turek, MD

    I have been suffering for too long now with epididymis and a hernia it is driving me crazy I went to a Doctor In Puerto Rico I got no treatment. I’m on Dialysis I live in the British Virgin Islands. Can’t take this pain any longer.


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