Epididymis – Tutorial
Please read Unit 12 – Introduction to Male Reproductive System Tissues prior to completing the activities in this chapter.
Introduction to the Epididymis
The epididymis is a highly coiled tube located within the scrotum just outside the posterior border of each testis. Although the epididymis are quite long, with an average length of 23 feet (7 meters), their small diameter and highly coiled structure allows them to be packed into a very small area adjacent to each testis. Each epididymis starts at its connection with efferent ductules on the posterior-superior region of the testis and then extends inferiorly along the entire posterior border of the testicle. The epididymis ends at its continuous connection with the vas deferens (ductus deferens) just inferior to the testis.
The epididymis serves to store and protect sperm as they gradually mature after being produced by the testes. Sperm are gradually moved through the lumen of the epididymis by a combination of fluid currents and peristaltic contraction of smooth muscle in the epididymis wall. It takes approximately three weeks for sperm to pass through the entire length of the epididymis on their way to the vas deferens. During this time, normal sperm gradually mature and damaged sperm are broken down by enzymes and eventually removed from the epididymis via venous circulation.
The lumen of the epididymis is lined with pseudostratified columnar cells with long stereocilia located on their apical surface. The stereocilia provide an abundance of surface area for the endothelium to secrete or absorb substances into or out of the lumen of the epididymis. Regulation of the quality of luminal fluid is critical to the proper development of maturing sperm.
Tutorial: Use the image slider below to learn more about the structure and characteristics of the epididymis.
Microscopy: Use the image slider below to learn how to use a microscope to study the epididymis on a microscope slide.
